V 
s  r    • 


THE  UNIVERSITY 

-V 


LIBRARY 


151 


Return  this  book  on  or  before  the 
Latest  Date  stamped  below.  A 
charge  is  made  on  all  overdue 
books. 

University  of  Illinois  Library 


;   i  v , 

If/lfl  13  1951 

per  « 

tin     -f  £  ICC1 
OUL    .'.  *— 

I  RPR  12195' 


.„.. 


MAR 


17 


71969 


1973 


SEP  02  1*71 


27214 


fff 

LIBRARY 

Q^~ 


«,'«?' Vf  V* 

BRARY     )] 


ON 


INTELLIGENCE. 


TAINE'S    WORKS. 


2  VOls. 


/.  NOTES  ON  ENGLAND. 

II.  ENGLISH  LITERATURE. 

III.   ON  INTELLIGENCE. 

IV.   THE  PHILOSOPHY  OF  GREEK  ART. 

V.    THE  PHILOSOPHY  OF  ART  IN  THE 

NETHERLANDS. 
VI.   THE  IDEAL  IN  ART. 
VII.  ITALY,  ROME  AND  NAPLES. 
VIII.  ITALY,  FLORENCE  AND  VENICE. 

HOLT  &  WILLIAMS,  Publishers 

25  BOND  STREET,  NEW  YORK. 


ON 


INTELLIGENCE 


BY 


H.  TAINE,  D.C.L.  OXON 


TRANSLATED  FROM  THE  FRENCH  BY 

T  .    D  .    H  A  Y  E 

AND     REVISED      WITH     ADDITIONS      BY     THE     AUTHOR 


NEW  YORK 

HOLT    &     WILLIAMS 
1872 


McCain  £  Co., 

STBRKOTYPEBS, 
NlWBCEOH,   N.   T. 


LANGE,  LITTLE  &   HILLHAN, 

PKl.VTKUS, 

108  to  114  WOOSTEB  ST.,  V.  Y. 


THE  Work  an  author  has  most  fully  meditated  ought  to 
be  honored  by  the  name  of  the  friend  whom  he  has  most 
respected.  I  dedicate  this  book  to  the  Memory  of  FRANZ 
WOEPKE,  Orientalist  and  Mathematician,  who  died  at  Paris, 

in  March,  1864. 

H.  TAINE. 


It  I 


IF  I  am  not  mistaken,  we  mean  nowadays  by  Intelligence, 
what  was  formerly  called  Understanding  or  Intellect — that 
is  to  say,  the  faculty  of  knowing ;  this,  at  least,  is  the  sense 
in  which  I  have  taken  the  word. 

At  all  events,  I  here  intend  to  examine  our  knowledge, 
that  is  to  say  our  cognitions,  and  nothing  else.  The  words 
faculty,  capacity,  pozver,  which  have  played  so  great  a  part  in 
psychology,  are  only,  as  we  shall  see,  convenient  names  by 
means  of  which  we  put  together,  in  distinct  compartments, 
all  facts  of  a  distinct  kind  ;  these  names  indicate  a  character 
common  to  all  the  facts  under  a  distinct  heading ;  they  do 
not  indicate  a  mysterious  and  profound  essence,  remaining 
constant  and  hidden  under  the  flow  of  transient  facts.  This 
is  why  I  have  treated  of  cognitions  only,  and,  if  I  have  men- 
tioned faculties,  it  has  been  to  show  that  in  themselves,  and 
as  distinct  entities,  they  do  not  exist. 

Such  a  precaution  as  this  is  very  necessary.  By  means  of 
it,  psychology  becomes  a  science  of  facts ;  for  our  cognitions 
are  facts ;  we  can  speak  with  precision  and  detail  of  a  sensa- 
tion, of  an  idea,  of  a  recollection,  of  a  prevision,  as  well  as  of 
a  vibration,  or  other  physical  movement  ^  in  the  one  case  as 
in  the  other  there  is  a  fact  in  question  ;  it  may  be  reproduced, 
observed,  described ;  it  has  its  precedents,  its  accompani- 
ments, its  consequents.  In  little,  well-selected,  important, 
significant  facts,  stated  with  full  details  and  minutely  noted, 
we  find  at  present  the  materials  of  every  science ;  each  of 
them  is  an  instructive  specimen,  the  head  of  a  rank,  a  salient 
example,  a  clear  type  to'  which  a  whole  row  of  analogous 
cases  conform ;  our  main  business  is  to  know  its  elements, 
how  they  arise,  in  what  manner  and  under  what  conditions 
they  combine,  and  what  are  the  constant  effects  of  combina- 
tions so  produced. 


viii  PREFA  CE. 

Such  is  the  method  it  has  been  attempted  to  follow  in 
this  work.  In  the  first  part,  the  elements  of  knowledge  have 
been  determined;  by  consecutive  reductions  we  have  arrived 
at  the  most  simple  elements,  and  have  passed  from  these  to 
the  physiological  changes  which  are  the  condition  of  their 
origin.  In  the  second  part,  we  have  first  described  the  mech- 
anism and  general  effect  of  their  combination  ;  then,  applying 
the  law  we  have  discovered,  we  have  examined  the  elements, 
formation,  certitude,  and  range  of  the  principal  kinds  of  our 
knowledge,  from  that  of  individual  things  to  that  of  general 
things,  from  the  most  special  perceptions,  previsions,  and 
recollections,  up  to  the  most  universal  judgments  and  axioms. 

In  these  inquiries,  Consciousness,  our  principal  instrument, 
is  not  sufficient  in  its  ordinary  state ;  it  is  no  more  sufficient 
in  psychological  inquiries  than  the  naked  eye  in  optical  in- 
quiries. For  its  range  is  not  great ;  its  illusions  are  many 
and  invincible  ;  it  is  necessary  continually  to  beware  of  it ; 
to  test  and  correct  its  evidence,  nearly  always  to  assist  it,  to 
present  objects  to  it  in  a  brighter  light,  to  magnify  them  and 
construct  for  its  use  a  kind  of  microscope  or  telescope  ;  at  all 
events,  to  arrange  the  surroundings  of  the  object,  to  give  it 
the  necessary  relief  by  means  of  contrasts,  or  to  find  beside 
it  indications  of  its  presence,  indications  plainer  than  it  is, 
and  indirectly  pointing  out  its  nature. 

Here  lies  the  principal  difficulty  of  the  analysis. — As  far 
as  pure  ideas  and  their  relations  with  names  are  concerned, 
the  principal  aid  has  been  afforded  by  names  of  numbers,  and, 
in  general,  by  the  notations  of  arithmetic  and  algebra ;  thus 
we  have  brought  again  into  light  a  great  truth  guessed  at  by 
Condillac,  and  which  has  lain  for  a  century  dormant,  buried, 
and  as  though  lifeless,  for  want  of  satisfactory  evidence. — As 
to  images,  their  effacement,  their  revival,  their  antagonist 
reductives,  the  necessary  magnifying  is  found  in  the  singular 
and  extreme  cases  observed  by  physiologists  and  medical 
men,  in  dreams,  in  somnambulism  and  hypnotism,  in  illusions 
and  the  hallucinations  of  sickness. — As  to  sensations,  signifi- 
cant instances  are  found  in  the  sensations  of,  sight,  and  es- 
pecially in  those  of  hearing.  By  means  of  such  evidence,  and 
of  the  recent  discoveries  of  physicists  and  physiologists,  we 


PREFACE.  ix 

have  attempted  to  construct  or  sketch  out  the  whole  theory 
of  elementary  sensations,  to  advance  beyond  the  ordinary 
bounds,  up  to  the  limits  of  the  mental  world,  to  indicate  the 
functions  of  the  principal  parts  of  the  brain,  to  conceive  the 
connection  of  molecular  nervous  changes  with  thought. — 
Other  abnormal  cases,  borrowed  both  from  students  of  in- 
sanity, and  from  physiologists,  have  enabled  us  to  explain 
the  general  process  of  illusion  and  rectification,  whose  suc- 
cessive stages  constitute  our  various  kinds  of  knowledge. — 
After  this,  to  elucidate  our  knowledge  of  bodies,  and  of  our- 
selves, valuable  indications  have  been  found  in  the  profound 
and  closely  reasoned  analysis  of  Bain,  Herbert  Spencer,  and 
Stuart  Mill,  in  the  illusions  of  persons  who  have  lost  limbs, 
in  all  the  different  illusions  of  the  senses,  in  the  education  of 
the  eye  in  persons  born  blind  who  have  recovered  their  sight 
by  operations,  in  the  singular  alterations  which  the  idea  of 
self  undergoes  during  sleep,  hypnotism,  and  madness. — We 
have  then  been  able  to  enter  upon  the  examination  of  the 
ideas  and  general  propositions  which  make  up  the  sciences, 
properly  so  called,  to  profit  by  Mr.  Mill's  acute  and  accurate 
inquiries  respecting  Induction,  to  establish  against  Kant  and 
Mill  a  new  theory  of  necessary  propositions,  to  study  by  a 
series  of  examples  what  is  termed  the  explanatory  reason  of 
a  law,  and  to  conclude  with  general  views  on  science  and 
nature,  while  pausing  before  the  metaphysical  problem  which 
'is  the  first  and  last  of  all. 

Between  psychology  thus  conceived  and  history  as  it  is 
now  written,  the  relationship  is  very  close.  For  history  is 
applied  psychology,  psychology  applied  to  more  complex 
cases.  The  historian  notes  and  traces  the  total  transforma- 
tions presented  by  a  particular  human  molecule,  or  group  of 
human  molecules ;  and,  to  explain  these  transformations, 
writes  the  psychology  of  the  molecule  or  group ;  Carlyle  has7 
written  that  of  Cromwell ;  Sainte-Beuve  that  of  Port  Royal ; 
Stendhal  has  made  twenty  attempts  on  that  of  the  Italians ; 
M.  Renan  has  given  us  that  of  the  Semitic  race.  Every  pers- 
picacious and  philosophical  historian  labors  at  that  of  a  man, 
an  epoch,  a  people,  or  a  race  ;  the  researches  of  linguists, 
mythologists,  and  ethnographers  have  no  other  aim ;  the 


x  PREFACE. 

task  is  invariably  the  description  of  a  human  mind,  or  of 
the  characteristics  common  to  a  group  of  human  minds;  and, 
what  historians  do  with  respect  to  the  past,  the  great  novel- 
ists and  dramatists  do  with  the  present.  For  fifteen  years  I 
have  contributed  to  these  special  and  concrete  psychologies ; 
I  now  attempt  general  and  abstract  psychology.  To  com- 
prise it  exhaustively,  there  would  be  required  a  theory  of 
the  Will  in  addition  to  the  theory  of  the  Intelligence ;  if  I 
may  judge  of  the  work  I  do  not  venture  to  undertake  by 
that  which  I  have  attempted  to  accomplish,  my  strength  is 
not  equal  to  this  ;  all  that  I  venture  to  hope  is  that  the  reader 
will  grant  me  his  indulgence,  in  consideration  of  the  difficulty 
of  the  task  and  the  length  of  the  effort. 

H.  TAINE. 

December,  1869. 


I     LIBRARY     I 

-^p-  Jf 

LlNOl^^ 

—  -~  "^^^ 


TABLE  OF  CONTENTS. 


PART  THE  FIRST 
THE  ELEMENTS  OF  KNOWLEDGE. 


BOOK  I. 
OF    SIGNS. 


CHAPTER    I. 

OF   SIGNS   IN  GENERAL  AND   OF    SUBSTITUTION. 

PAOB 

I.  Different  examples  of  signs — A  sign  is  a  present  experience  which 
suggests  to  us  the  idea  of  a  possible  experience I 

II.  Names  are  a  species  of  signs — Examples — Proper  names — A  proper 
name  is  a  sensation  or  image  of  the  eye  or  ear,  which  calls'  up  in  us 
a  group  of  more  or  less  definite  images 2 

III.  Frequently  this  group  is   not  called  up — Examples — The  name  then 
becomes  the  substitute  of  the  group 2 

IV.  Other  examples  of  substitution — In   arithmetic — In  algebra — Nature 
and  importance  of  substitution ,.      4 

CHAPTER  II. 

OF  GENERAL  IDEAS    AND    SIMPLE    SUBSTITUTION. 

I.  Proper  and  common  names — Importance  of  common  or  general  names 
— They  are  the  first  terms  of  couples — The  second  terms  of  such 
couples  are  general  and  abstract  characters 7 


ii  CONTENTS. 

PAOE 

II.  Consequences  of  this — Experience  of  such  second  terms  is  impossible 

— Reasons  of  this  impossibility — Different  examples — Difference  be- 
tween the  vague  image  aroused  by  the  name,  and  the  precise  charac- 
ter denoted  by  the  name — Difference  between  the  sensible  image  and 
pure  idea 8 

III.  Actual  formation  of  a  general  idea — That  which  is  evolved  in  us, 
when  we  have  seen  a  series  of  similar  objects,  is  a  final  tendency 
resulting  in  a  metaphor,  a  sound,  or  an  expressive  gesture — Contem- 
porary instances — Early  instances — A  general  name  is  the  residuum  of 
an  expressive  sound — When  we  conceive  a  general  quality,  there  is 
nothing  more  in  our  minds  than  a  tendency  to  name,  and  a  name — 
This  name  is  the  substitute  of  an  impossible  experience 10 

IV.  A  general  Idea  is  nothing  but  a  name  provided  with  two  characters — 
The  first  is  the  property  of  being  called  up  on  the  perception  of  each 
individual  of  a  class — The  second,  the  property  of  calling  up  in  us 
images  of  individuals  of  this  class,  and  of  this  class  only — By  these 
two  properties,  the  general  name  corresponds  exclusively  to  the 
general  quality,  and  becomes  its  mental  representative — Utility  of 
this  substitution 12 

V.  Formation  of  general  names  in  the  case  of  little  children — The 
faculty  of  language  is  founded  on  the  consecutive  tendencies  which 
survive  the  experiences  of  similar  individual  cases,  and  correspond 
to  what  there  is  in  common  to  these  individuals— rExamples  of  this 
tendency  in  children — Special  meanings  given  by  them  to  the  names 
we  teach  them — Originality  and  variety  of  their  invention — Their 
tendencies  to  name  finally  coincide  with  ours — Acquisition  of  lan- 
guage— Difference  between  human  and  animal  intelligence 15 

VI.  Passage  from  abstract  to  collective  names — The  name  which  denoted 
a  general  quality  denotes  a  group  of  general  qualities — Examples — 
The  name  then  becomes  the  substitute  of  several  other  names,  and  the 
mental  representative  of  a  group  of  general  qualities — These  sub- 
stitutes are  what  we  term  Ideas 19 

CHAPTER  III. 

OF   GENERAL  IDEAS   AND   REPEATED   SUBSTITUTIONS. 

I.  Certain  General  Characters  do  not  produce  in  us  a  distinct  impression — 
They  are  therefore  incapable  of  exciting  in  us  a  general  tendency 
and  a  name — Indirect  process  by  which  we  arrive  at  conceiving 
thtm — Example  in  the  case  of  numbers — Their  mental  representa- 
tive is  a  name  of  number — Formation  of  names  of  numbers — Series 
of  superimposed  substitutions — Our  idea  of  a  number  is  that  of  a 
name  substituted  for  another  name  combined  with  unity 22 

II.  Examples  in  Geometry — Our  Idea  of  a  circle  is  not  the  sensible 
figure  we  imagine,  but  a  group  of  combined  names,  mental  represen- 


CONTENTS.  xiii 

PAGE 

tatives  of  certain  abstract  characters — Substitution  of  the  formula 
for  the  impossible  experience — We  conceive  the  ideal  object  by 
means  of  its  formula — Universal  employment  of  substitution  in 
mathematics 25 

III.  Examples  in  the  cases  of  Infinite  Series — Time  and  Space — In  the 
case  of  an  infinite  series  or  quantity,  we  do  not  conceive  the 
totality  of  its  terms,  but  certain  of  its  terms,  and  one  of  their 
abstract  characters  represented  in  us  by  a  name — Substitution  of 
the  formula  for  the  impossible  experience — We  conceive  the  infinite 
series  or  quantity  by  means  of  its  formula 27 

IV.  Summary — Our  general  Ideas  are  names,  substitutes  for  impossible 
experiences — Psychological  Illusion  which  consists  in  distinguishing 
the  idea  from  the  name — Singular  effects  and  general  cause  of  this 
illusion — It  is  natural  that  signs  should  cease  to  be  observed,  and 
end  by  being  considered  as  mere  nothings — False  theories  on  the 
pure  spirit — The  mental  representative  we  term  a  pure  idea,  is 
never  more  than  a  name  pronounced,  understood,  or  imagined — 
Names  are  a  class  of  Images — The  Laws  of  Ideas  are  reduced  to  the 
Laws  of  Images .  2q 


BOOK  II. 
OF    IMAGES. 


CHAPTER  I. 

OF  THE  NATURE  AND  REDUCTION  OF  IMAGES. 

I.  An  Experience — An  Image  is  a  spontaneously  reviving  sensation, 
usually  less  energetic  and  precise  than  the  sensation  proper — The 
force  and  precision  of  the  image  varies  in  individuals  and  according 
to  its  kinds — Personal  Instances — Instances  of  children  accustomed 
to  calculate  mentally — Precocious  mathematicians — Blindfolded  chess- 
players— Painters  who  can  draw  portraits  or  make  copies  from  memory 
— Schools  of  Art  in  which  this  faculty  is  cultivated — Other  instances 
of  the  voluntary  revival  of  visual  sensations — Sensations  of  the  other 
sense  have  their  corresponding  images — Images  corresponding  to  au- 
ditor/ s^a.-v  tions — Examples 33 

II.  Circumstances  increasing  the  precision  and  force  of  the  image — In 
such  a'  ca-e  it  becomes  more  and  more  like  the  sensation — Instances 
in  which  the  sensation  is  recent — Instances  in  which  the  sensation 
is  immediately  expected — Examples  of  images  corresponding  to 
sensations  of  hearing,  of  sight,  of  smell,  of  taste,  of  touch — Equal 
and  similar  effects  of  the  image  and  the  corresponding  sensation — 
In  these  cases  the  image  is  taken,  at  least  momentarily,  for  the 
sensation  corresponding  to  it 39 


iv  CONTENTS. 

PAGB 

III.  How,  in  spite  of  this,  it  differs  from  the  corresponding  sensation — 
The  illusion  accompanying  it  is  speedily  rectified — The  image  inva- 

.  riably  comprises  an  illusion  of  greater  or  less  duration — Dugald 
Stewart's  Law — Instance  of  an  American  preacher — Testimony  of 
M.  Flaubert — Instance  of  an  English  painter — Evidence  of  a  chess- 
player— Observations  of  Goethe  and  of  M.  Maury — Voluntary  hallu- 
cinations— Various  circumstances  under  which  the  image  becomes  hal- 
lucinatory— These  extreme  cases  are  evidence  as  to  the  normal  state 
— In  the  normal  state,  the  illusion  is  at  once  destroyed — It  is  destroyed 
by  the  presence  of  an  antagonist  or  reductive 41 

IV.  Cases  in  which  the  contradicting  sensation  is  too  feeble  or  is  annulled 
— Hypnagogic  Hallucinations — Experiments  of  M.  Maury — Personal 
experience — Passage  from  the  simple  image  to  the  hallucinatory  image, 
and  from  that  to  the  simple  image — Other  cases  in  which  the  contra- 
dictory  sensation    is   annulled — Wounds    in    battle — Hallucinations 
strictly  so-called — Hallucinations  of  sight  after  the  prolonged  use  of 
the  microscope — Partial  restoration  of  the  antagonist  sensation — Path- 
ological instances — In  such  cases,  the   hallucination  is  destroyed — 
Story  of  Nicolai — General  means  of  destroying  the  hallucination — 
Case  in  which  a  sensation   calls  up  an  illusion  properly  so-called — 
Story  of  Dr.  Lazarus — In  such  cases,  the  suppression  of  the  exciting 
sensation  destroys  the  illusion 46 

V.  Other  antagonists — Reminiscences  and  general  judgments  form,  by 
their  combination,  a  body  of  auxiliary  reductives — Their  influence  is 
more  or  less  prompt  and  energetic — Different  examples — Cases  in 
which  their  influence  is  not  sufficient — The  antagonistic  sensation, 
which  is  the  special  reductive,  is  then  annulled — Examples  in  intoxi- 
cation and  illness — The  patient  then  concludes  the  hallucination  to  be 
an  hallucination — Instances  in  which  all  reductives  are  annulled,  or 
of  complete  mental  alienation — Remarkable  case  recorded  by  Dr. 
Lhomme 60 

VI.  General  views  as  to  the  thinking  being — The  mind  is  a  collection  of 
images,  like  a  polypus — General  views  as  to  the  normal  reasonable 
wakeful  state — Mutual  equilibrium  of  various  images — Constant  re- 
pression of  the  rising  hallucination  by  special  reductives — Necessity 
of  sleep — Summary  as  to  images — Their  characters  and  relations  to 
sensation — The  image  is  the  substitute  of  the  sensation 66 

CHAPTER  II. 

LAWS   OF   THE    REVIVAL  AND   OBLITERATION   OF    IMAGES. 

I.  The  image  of  a  sensation  may  rise  after  a  considerable  interval — Ex- 
amples— It  may  then  rise  without  having  done  so  during  the  interval 
— Examples — Singular,  morbid  instances  of  the  revival  of  images 
which  seemed  obliterated — Recollection  of  a  language  learned  in 


CONTENTS.  xv 

PAGE 

childhood,  and  afterwards  forgotten — Automatic  recollection  of  a  series 
of  sounds  heard  mechanically — Probability  that  every  sensation  we 
experience  preserves  an  indefinite  aptitude  for  revival 70 

II.  Different  sensations  have  not  all  this  aptitude  for  revival  in  an  equal  de- 
gree— Examples — General  circumstances  augmenting  this  aptitude — 
Extreme  attention,  voluntary  or  involuntary — The  persistence  of  im- 
pressions acquired  in  fancy  is  thus  explained — In  what  attention  con- 
sists— Competition  between  our  different  images — The  Law  of  Natural 
Selection  is  applicable  to  Mental  Events — Another  circumstance  which  {/* 
augments  the  aptitude  for  revival — Repetition — Examples — Why  these 
two  circumstances  augment  the  aptitude  for  revival 73 

III.  Special  circumstances  calling  up,  at  a  particular  moment,  one  image 
rather  than  another — Example — The  reviving  image  has  already, 
either  by  contiguity  or  by  similitude  commenced  to  revive — Why  par- 
tial revival  excites  complete  revival 77 

IV.  Absence  of  the  indicated  circumstances — Want  of  attention — Want  of 
repetition — Enormous  number  of  sensations  which  thus  lose  their  apt- 
itude for  revival — Cases  in  which  two  tendencies  neutralize  each  other 
— Repetition  and  variety  of  experience  blunt  the  image — Origin  of 
general  names,  and  of  the  vague  images  accompanying  them — The 
majority  of  our  sensations  do  not  exist  in  our  minds  in  the  state  of  ex- 
press images,  but  in  the  state  of  dull  consecutive  tendencies.  ...  80 

V.  General  views  as  to  the  history  of  images  and  ideas — They  are  in  per- 
petual conflict  for  preponderance — Effect  of  internal  laws  and  external 
incidents  in  determining  which  preponderates — Temporary  oblitera- 
tion, prolonged  or  definitive,  of  a  whole  group  of  images — Partial  and 
total  paralysis  of  memory,  excited  by  fatigue,  loss  of  blood,  blows, 
apoplexy — Examples — Forgetfulness  of  names — Forgetfulness  of 
spoken  names,  but  not  of  the  meaning  of  written  names — Restoration  of 
lost  faculties — Appearance  of  new  faculties — Examples — Aptitudes  and 
faculties  are  connected  with  the  organic  state — Possibility  of  two  or-  f 
ganic  states  severed  from  one  another,  and  recurring  periodically  in  the 
same  individual — Case  of  an  American  lady — Two  lives  and  two  men- 
tal states  may  thus  be  met  with  in  the  same  person — Instances — In 
what  the  moral  personality  consists — Two  moral  personalities  may  suc- 
ceed cne  another  in  the  same  individual — What  forms  the  continuity 
of  a  distinct  moral  person  is  the  continuous  revival  of  the  same  dis- 
tinct group  of  images 84 


BOOK  III. 
OF    SENSATIONS. 


CHAPTER  I. 

OF   SENSATIONS   OF   HEARING  AND  THEIR   ELEMENTS. 

PAO1 

I.  Reduction  of  ideas  to  a  class  of  images,  and  of  images  to  a  class  of 
sensations — Enumeration  of  ihe  principal  kinds  of  sensations — What 
is  meant  by  the  word  sensation — Distinction  between  the  property  of 
the  external  object  which  excites  the  sensation,  and  the  sensation  it- 
self— Distinction  between  the  crude  sensation  and  the  apparent  posi- 
tion attributed  to  it  by  consciousness — Distinction  between  the  sensa- 
tion and  the  state  of  the  nerves  and  nervous  centres — Special  and 
primitive  character  of  sensation 93 

II.  Classification  of  sensations  by  Gerdy,  Mueller,  Longet,  and  Bain — Its 
practical  convenience  and  scientific  inadequacy — In  what  the  classified 
sensations  differ  from  other  facts  also  classified — We  cannot  distin- 
guish the  elements  of  sensations — Physical  and  Physiological  Science 
cannot  distinguish  these  elements,  but  only  the  conditions  of  whole 
sensations — Sensations  appear  to  be  irreducible  to  other  more  simple 
data — Psychology  seems,  with  reference  to  them,  what  Chemistry  is 
with  reference  to  simple  bodies 95 

III.  Psychology  stands  with  reference  to  them  as  Chemistry  did  with  refer- 
ence to  Chemical  compounds  before  the  discovery  of  simple  bodies — 
Analysis  of  the  sensations  of  sound— Various  kinds  of  sounds — They 
are,  in  appearance,  irreducible  to  one  another — The  Wheel  of  Savart 
and  the  Siren  of  Helmholtz — Musical  Sound — The  continuous  sensa- 
tion is  then  composed  of  successive  elementary  sensations — Instance 
of  very  deep  sounds — We  can  distinguish  in  these  the  successive  ele- 
mentary sensations — Each  of  them  has  a  certain  duration,  and  passes 
from  a  minimum  to  a  maximum  of  intensity — Instance  of  certain  mu- 
sical notes — Savart's  experiment — Enormous  number  of  elementary 
sensations  succeeding  in  a  second  to  form  a  whole  sensation  of  acute 
sound — Their  number  increases  in  proportion  to  the  acuteness  of  the 
sound — In  this  case  the  elementary  sensations  cease  to  be  distinguish- 
able by  consciousness — Appearance  which  the  elementary  sensation 
must  therefore  assume — It  actually  assumes  this  appearance — The  char- 
acters of  deep,  acute,  high,  low,  full,  drawn-out,  firm,  vibrating,  found 
in  the  total  sensation  are  explained  by  the  arrangement  of  the  element- 
ary sensations 99 


CONTENTS.  xvii 

PAQB 

IV.  Continuation  of  the  analysis  of  sensations  of  sound — Explanation  of 
the  sensation  of  intensity — Explanation  of  the  sensation  of  tone — 
Discovery  of  Helmholtz — Explanation  of  the  sensation  of  noise — Con- 
struction of  the  whole  of  the  total  sensations  of  sound  by  means  of  the 
elementary  sensations  of  sound — Analysis  of  the  elementary  sensation 
of  sound — It  is  composed  of  a  maximum,  a  minimum,  and  an  infinite 
number  of  intermediate  states 104 


CHAPTER  II. 

SENSATIONS   OF   SIGHT,  OF   SMELL,  OF   TASTE,  OF   TOUCH,  AND  THEIR   ELEMENTS. 

I.  Total  sensations  of  sight — The  spectrum — Infinite  number  of  total 
sensations  of  color — There  are  at  least  three  elementary  sensations  of 
color — It  is  sufficient  to  admit  three — Theories  of  Young  and  Helmholtz 
— Experimental  confirmation  of  this  theory — Partial  paralysis  of  the 
aptitude  for  experiencing  sensations  of  color — Experience  which  raises 
to  a  maximum  the  sensation  of  violet  and  of  red — The  three  elemen- 
tary sensations  are  those  of  red,  violet,  and  probably  green.  ...  no 

II.  Construction  of  the  various  sensations  of  spectral  color  by  the  combina- 
tions of  these  elementary  sensations — Sensation  of  white — Comple- 
mentary colors — Law  governing  the  mixture  of  spectral  colors — Their 
saturation  and  their  proximity  to  white — Sensation  of  black,  or  \rant 
of  retinal  sensation — It  furnishes  a  new  element  for  the  composition  of 
the  various  total  sensations  of  color — Different  examples — Summary — 
We  cannot  distinguish  by  consciousness  the  elements  of  the  elemen- 
tary sensations  of  color — Why — Analogy  of  these  elementary  sensa- 
tions and  the  elementary  sensations  of  sound — Proof  that  there  are 
elements  in  these  as  in  the  others — Wheatstone's  Experiment — Enor- 
mous number  of  successive  elements  composing  an  elementary  sensa- 
tion of  color — Indications  and  conjectures  as  to  the  ultimate  elements 
— Consciousness  perceives  aggregates  only 114 

III.  Total  sensations  of  taste  and  smell — Increased  difficulties — Reason 
of  these  difficulties — Preliminary  distinctions — Smell — Sensations  of 
smell  strictly  so  called  must  be  separated  from  those  of  nasal  touch — 
Examples — And  from  those  of  the  alimentary  canal — Examples — And 
from  those  of  the  nerves  of  the  air  passages — Examples — We  thus  iso- 
late sensations  of  pure  smell — Their  types — Taste — Sensations  of  taste 
strictly  so  called  must  be  separated  from  other  accompanying  sensations 
— Accompanying  sensations  of  smell  and  of  nasal  touch — Accompany- 
ing sensations  of  temperature  and  touch  in  the  mouth — Sensations  of 
taste  proper,  vary  with  the  different  parts  of  the  mouth — Experiments 
of  Guyot  and  Admyrault — Extreme  complication  of  the  sensations  of 
taste  and  even  those  of  pure  taste — Their  types — The  action  of  the 
olfactory  and  gustatory  nerves  probably  has,  as  immediate  antecedent, 
a  chemical  combination,  that  is  to  say  a  system  of  molecular  displace- 


>ui  CONTENTS. 

PAGE 

ments — Analogy  between  this  antecedent  and  the  vibration  of  ether 
which  excites  the  action  of  the  retina — Indications  as  to  the  mode  of 
action  of  the  olfactory  and  gustatory  nerves — Most  probably  it  consists 
in  a  succession  of  actions,  similar  to  one  another  and  extremely  short, 
each  of  which  excites  an  elementary  sensation  of  smell  or  taste — 
Theory  of  the  four  special  senses — Each  of  them  is  a  special  idiom 
constructed  to  represent  a  single  order  of  facts — General  theory  of 
the  senses — They  are  all  idioms — The  sense  of  touch  is  a  general 

idiom 117 

IV.  Total  sensations  of  touch — Increasing  difficulties — Reason  of  these 
difficulties — Preliminary  distinctions — First  group  of  sensations  of 
touch  ;  muscular  sensations — Cases  of  paralysis  in  which  they  are  ab- 
sent— Observations  of  Landry — The  two  groups  of  nerves  are  distinct 
— The  two  groups  of  sensations  are  similar — There  are  three  kinds  of 
sensations  for  all  the  nerves  of  touch — Sensations  of  contact,  of  tem- 
perature, of  pleasure  and  pain — Each  of  these  three  kinds  may  be 
singly  preserved  or  abolished  —  Observations  on  sick  persons — 
Known  conditions  of  each  kind — Experiments  and  observations — 
Opinion  of  Weber — These  distinctions  are  distinct  types  of  activity 
for  the  same  nerve — Experiments  of  Fick — The  different  characters 
we  find  in  the  aggregate  sensations  of  contact,  temperature,  pleasure, 
and  pain,  are  capable  of  being  explained  by  the  different  arrangement 

of  the  same  elementary  sensations 126 

V.  Summary — Blanks  in  the  theory — Researches  which  may  supply  them 
— The  nervous  action  which  excites  a  sensation  is  never  more  than  a 
displacement  of  nervous  molecules — To  this  elementary  displacement 
corresponds  an  elementary  sensation — The  differences  of  total  sensa- 
tions are  all  caused  by  the  diversities  of  grouping  of  the  same  elemen- 
tary sensations — General  process  and  economical  method  followed  by 
nature  in  the  construction  of  the  mind 137 


BOOK  IV. 

OF  THE   PHYSICAL   CONDITIONS   OF   MENTAL  EVENTS. 


CHAPTER   I. 

OF  THE  FUNCTIONS  OF  THE  NERVOUS  CENTRES. 

I.  Conclusion  of  psychological  analysis — Commencement  of  the  physio- 
logical analysis 143 

II.  The  external  physical  event  is  an  accessory  and  distant  condition 
of  the  sensation — It  only  excites  the  sensation  through  a  medium  ; 
the  excitation  of  the  nerve — Different  kinds  of  sensitive  nerves — 
Each  has  its  special  action — The  action  of  each  is  different — Every 


CONTENTS.  xix 

PAGE. 

nerve  is  capable  of  spontaneous  action — Subjective  and  consecutive 
sensations — Altered  sensations  —  Experiments  and  observations  of 
Physiologists 144 

III.  The  nerve  is  a  simple  conductor — Molecular  action  must  be  propa- 
gated from  its  peripheral  to  its  central  extremity — Whatever  may  be 
the  point  of  its  course  from  which  the  molecular  action  starts,  the  sen- 
sation is  the  same — Illusions  of  persons  who  have  suffered  amputa- 
tions— The  action  of  the  nerves  only  excites  sensation  through  a  me- 
dium, the  action  of  the  nervous  centres — In  what  the  molecular  move- 
ment propagated  in  the  nerve  consists — It  may  be  propagated  in  both 
directions — Experiments   of  Bert   and  Vulpian — If  any  nerve  when 
irritated  excites  a  certain  sensation  it  is  from  its  central  extremity  be- 
ing in  connection  with  some  portion  of   the  nervous  centres — The 
simple  excitation  of  the  nervous  centres  is  sufficient  to  produce  sensa- 
tion— Proof  by  hallucinations — Instances  observed  by  writers  on  in- 
sanity— Hallucinations  following  the  prolonged  use  of  the  microscope 
— Observations  of  M.  Robin — Action  of  the  nervous  centres  is  the 
necessary  and  sufficient  condition  of  sensation 147 

IV.  The  different  portions  of  the  encephalon — The  rachiclian  bulb — When 
it  alone  is  preserved,  there  are  no  longer  sensations  strictly  so  called — 
Experiments  of  Vulpian — Distinction  between  the  reflex  cry  and  cry 
of  pain — The   annular  protuberance — Experiments   of  Longet   and 
Vulpian — The  action  of  the  protuberance  is  the  sufficient  and  neces- 
sary condition  of  sensations  of  touch,  of  hearing,  and  of  taste — The 
corpora  bigemina  or  quadrigemina — Experiments  of  Flourens,  Longet, 
and  Vulpian — The  action  of  these  tubercles  is  the  sufficient  and  neces- 
sary condition  of  sensations  of  sight — Probable  existence  of  another 
centre  whose  action  is  the  necessary  and  sufficient  condition  of  sensa- 
tions of  smell 152 

V.  The  action  of  these  centres  is  the  sufficient  and  necessary  condition  of 
crude  sensations — Accordance  of  the  results  of  Physiology  and  Psychol- 
ogy— Structure  of  the  encephalon — The  cerebral  lobes  or  hemispheres 
— Their  gray  substance — Relation  of  intelligence  to  the  volume  and 
extent  of  this  gray  substance — The  action  of  the  cerebral  lobes  is  the 
sufficient  and  necessary  condition  of  images  or  reviving  sensations, 
and  consequently  of  all  the  mental  operations  which  outstep  the  limits 
of  crude  sensation — Experiments  of  Flourens  and  Vulpian — Accord- 
ance of  pathological  observations  156 

VI.  Internal  structure  of  the  cerebral  lobes — Their  white  substance  is 
conducting  only — Functions  of  the  gray  substance — Physiological  and 
pathological  proofs — Gaps  in  physiology — The  various  departments  of 
gray  substance  fulfil  identical  functions,  and  form  a  group  of  repeating 
and  multiplying  organs — Pathological  and  physiological  proofs — One 
hemisphere  supplies  the  place  of  the  other — A  portion  of  the  hemi- 
spheres, if  large  enough,  supplies  the  place  of  the  rest — Application  of 
psychological  data — One  element  of  the  hemispheres  repeats  the  action 


CONTENTS. 


of  the  sensory  centres,  and  transmits  it  to  the  other  elements — Why 
the  magnitude  of  the  hemispheres  and  the  development  of  their  cor- 
tical layer  increases  the  extent  of  the  intelligence — Mechanism  of  the 
formation,  survival,  and  indefinite  repetition  of  images — Physiological 
causes  of  the  conflict,  preponderance,  and  succession  of  images — La- 
tent images — To  what  physiological  state  of  the  cerebral  elements 
they  correspond — The  predominant  image  corresponds  to  a  physiolo- 
gical action  propagated  through  the  majority  of  the  cerebral  elements 
— The  image  is  so  much  the  weaker  as  the  cerebral  elements  in  which 
the  corresponding  physiological  action  takes  place  are  the  less  numer- 
ous— All  we  can  know  by  consciousness  are  aggregates — The  latent 
state  is  but  the  rudimentary  state 162 

VII.  Summary — Beneath  aggregates  observable  by  consciousness  lie  their 
elements,  which  are  invisible  to  consciousness — Characters  and  signs 
of  elementary  mental  events — Reflex  phenomena — Experiments  of 
Vulpian,  Landry,  Duges,  and  Claude  Bernard — Indications  of  mental 
events  in  the  inferior  and  secondary  nervous  centres — The  segments 
of  the  maiTOw — Probable  analogy  of  these  events  and  elementary  sen- 
sations— Successive  degrees  and  constant  correspondence  of  the  molec- 
ular movement  of  a  nervous  centre,  and  the  mental  event  .  .  .  170 


CHAPTER  II. 

RELATIONS  OF  THE  FUNCTIONS  OF  THE  NERVOUS  CENTRES,  AND  MENTAL  EVENTS. 

I.  Distinction    of    physical  and   moral  —  The  second  order  of  facts  is 

connected  with  the  first — This  connection  seems  inexplicable — Ad- 
vantage of  the  preceding  reductions  and  of  the  theory  of  elementary 
sensations 178 

II.  Situation   of  the  difficulty — Notion   of  molecular   movement  in  the 
cells  and  fibres  of  the  nervous  centres — Even  if  we  suppose  it  to  be 
completely  elucidated  we  still  find  its  idea  and  that  of  a  sensation  are 
irreducible  to  one  another 179 

III.  Another  method  of  investigation — The  two  ideas  may  be  irreducible 
to  one  another  without  the  two  orders  of  facts  being  irreducible  to  one 
another — Two  objects  seern  different  to  us  when  we  acquire  their 
ideas  in  different  ways — Examples — This  general  law  is  applicable  to 
the  present  case — Absolute  difference  between  the  process  by  which 
we  acquire  the  idea  of  a  sensation  and  the  process  by  which  we  ac- 
quire the  idea  of  the  nervous  centres  and  their  molecular  movements 

— The  two  ideas  must  be  irreducible  to  one  another iSl 

IV.  Another  series  of  reasons — The  aspect  of  the  sensation,  and  that  of  its 
ultimate  elements  must  be  wholly  and  entirely  different — Hypothesis 
of  two  heterogeneous  events — Hypothesis  of  one  and  the  same  event 
known  under  two  aspects — Results  of  the  first  hypothesis — It  is  un- 


CONTENTS.  xxi 

PAUK 

scientific — Probability  of  the  second — Of  the  two  points  of  view  that 
of  consciousness  is  direct,  and  that  of  external  perception  is  indirect — 
The  molecular  movement  is  but  a  sign  of  the  mental  event — Direct 
and  remarkable  confirmation  of  the  second  hypothesis — The  sensation 
and  its  elements  are  the  only  real  events  of  nature — Rudimentary  and 
infinitesimal  sensations — The  nervous  system  is  but  an  apparatus  of 
complication  and  perfectionment  —  Presence  of  elementary  mental 
events  in  the  whole  organized  world — Their  probable  presence  below 
this — Double  scale  and  corresponding  stages  of  the  physical  and 

moral  world 184 

V.  The  two  faces  of  nature — Clear  and  obscure  portions  of  the  physical 
world — Clear  and  obscure  portions  of  the  moral  world — To  the  clear 
portions  of  the  one  correspond  obscure  portions  of  the  other,  and  re- 
ciprocally— Each  of  them  by  its  bright  parts  lightens  up  the  obscuri- 
ties of  the  other — Comparison  of  the  two  aspects  to 
text  accompanied  to  an  incomplete  translation  .  .  /y^.  .  \>J 


CHAPTER    III. 

THE  HUMAN   PERSON  AND   THE  PHYSIOLOGICAL 

^s/<. 

I.  Usual  opinion  as  to  the  human  personality  and  its  faculufei^-Me'aft*     .  ,  <. 

ing  of  the  word  faculty  or  power — Mechanical  forces — F^jrce  01" 
These  words  do  not  denote  any  occult  being — All  they  denote  is  a 
character  of  an  event,  that  is  to   say,  its  particularity  of  being  con- 
tantly  followed  by  another — Metaphysical  illusion  erecting  forces  into 
distinct  essences 191 

II.  Metaphysical  illusion  forming  of  self  a  distinct  substance — Meaning  of 

the  verb  to  be — Our  successive  events  are  the  successive  components 

of  our  self — In  what  the  faculties  of  the  Ego  consist — Examples    .     .  194 

III.  Progressive  ruin  of  scholastic  entities — Scientific  idea  of  forces  and  be- 
ings— Its  application  to  self  and  to   matter — Mathematical  'idea   of 
atoms — A  real  substance  is  nothing  more  than   a  distinct  series  of 
events — A  force  is  nothing  more  than  the  property  of  one  of  these 
events,  to  be  followed  by  one  of  the  same  series  or  of  another  series — 
Idea  of  nature 198 

IV.  The  series  which  makes  up  the  Ego  is  a  fragment  in  the  whole  aggre- 
gate of  animal  functions — Physiological  aspect — Order  of  nervous  cen- 
tres and  nervous  activities — The  ganglia,  the  segments  of  the  marrow, 
the  layers  of  the  encephalon — Pyschological  aspect — Order  and  in- 
creasing complication  of  the  mental  events  indicated  or  proved  in  the 
different  centres — In  proportion  as  the  animal  descends  the  zoological 
scale,  the  different  centres  become  more  and  more  independent — Ex- 
periments and  observations  of  Duges,  Landry,  and  Vulpian — Funda- 
mental plurality  of  the  animal — The  individual,  animal  or  human,  is 
nothing  more  than  a  svstem  .  200 


CONTENTS. 


PART  THE  SECOND. 
OF   THE   DIFFERENT   KINDS    OF    KNOWLEDGE. 


BOOK  I. 

THE   GENERAL   MECHANISM   OF   KNOWLEDGE. 


CHAPTER   I. 

OF     ILLUSION.  PAGE 

I.  Summary  of  the  first  part — Elements  of  human  knowledge — Principal 
compounds  formed  by  their  combinations — The  formation  and  rectifi- 
cation of  illusions  are  two  processes  by  which   our  various  kinds  of 
^      knowledge  are  built  up  in  our  minds 205 

II.  Examples — Illusion  produced  at  the  theatre — Optical  illusions — Illu- 
sions of  persons  who  have  lost  limbs — The  sufficient  condition^  of  be- 
lief or  affirmative  judgment  is  the  presence  of  the  ordinary  sensation — 
It  does  not  matter  whether  the  sensation  be  accompanied  by  its  ordin- 
ary antecedents — Proofs — When  the  condition  of  the  mental  process  is 
given,  it  is  pursued  blindly,  as  in  the  case  of  the  vital  process  .  .  .  207 

III.  Consequences  of  this — External  perception  is  a  true  hallucination — Ex- 
amples— In  the  normal  and  ordinary  state,  our  dream  within  corre- 
sponds to  things  without — Psychological  illusion  as  to  external  percep- 
tion— We  are  tempted  to  take  it  for  a  simple  spiritual  act — Analogous 
psychological  illusion  as  to  other  acts  of  cognition 210 

IV.  Part  played  by  the  image  which  is  substituted  for  sensation — It  excites 
the  same  hallucinatory  process — Examples — Case  in  which  this  pro- 
cess becomes  developed — Observations  of  M.  Maury  on  hypnagogic 
hallucinations — Hypnotism  and  somnambulism — Braid's  experiments 
on  suggestion — Cases  mentioned  by  Dr.  Carpenter — Experiments  of 
Dr.  Tuke — Predominance  of  images  and  of  the  action  of  the  hemi- 
spheres   •  213 

V.  Consequences — Presence  of  images  in  all  sensible  representations  and 
in  all  pure  ideas — And  again,  in  all  external  perceptions,  recollections, 


CONTENTS.  xxKi 

PAGE 

previsions,  and  acts  of  consciousness — General  tendency  of  the  mind 
to  hallucination — In  all  our  mental  operations,  there  is  an  hallucina- 
tion, at  all  events  in  an  incipient  state — Examples  of  its  development 
—  Mental  phrases  which  become  external  voices — Effaced  images 
which,  on  revival,  become  hallucinatory — Our  various  mental  opera- 
tions are  but  the  various  stages  of  this  hallucination 219 


CHAPTER  II. 

OF    RECTIFICATION. 

I.  Example  of  rectification — Case  of  reverie — Double  effect  of  the  antago- 
nist reductives — The  representation  grows  weak  and  ceases  to  appear 
a  real  object — Even  when  the  representation  remains  distinct  and 
colored,  it  ceases  to  appear  a  real  object — General  mechanism  of  this 
last  rectification — It  consists  in  a  negation — It  is  accomplished  by  the 
attachment  of  a  contradictory  representation — Various  points  on  which 
the  contradiction  may  attach 226 

II.  Applications — Rectification  of  theatrical  illusions — Rectification  of 
optical  illusions — Rectification  of  illusion  by  a  person  who  has  lost  a 
limb — Rectification  by  a  person  under  hallucination  of  his  illusion — 
The  illusion  is  checked  either  at  its  first,  or  at  one  of  its  subsequent 
stages 227 

III.  Various  states  and  degrees  of  the  contradictory  representation — Case 
in  which  it  is  feeble — Case  in  which  it  is  intense — Case  in  which  it  is 
transformed  into  a  sensation — Physiological  theory  of  these  different 
states — Persisting  action  of  the  centres  of  sensation — Reflected  action 

of  the  hemispheres  on  the  centres  of  sensation 230 

IV.  Abnormal  state  and  maximum  degree  of  the  representation — The  an- 
tagonist sensation  is  then  ineffectual  and  the  contradictory  represen- 
tation is  not  a  sufficient  reductive — The  contradictory  representation 
is  only  effectual  upon  groups  of  images  of  no  higher  degree  than  its 
own 233 

V.  Normal  state  of  wakefulness — Example — The  first  stage  of  rectifica- 
tion, recollection — The  present  image  appears  as  a  past  sensation — 
Recollection,  like  external  perception,  is  an  illusion  which  results  in 
a  cognition — Our  present  dream  corresponds  to  an  anterior  sensation 
— Psychological  illusion  respecting  memory — We  are  tempted  to  take 
the  knowledge  of  our  past  states  for  a  simple  spiritual  act  ....  235 

VI.  Mechanism  of  memory — Examples — The  present  sensation  negatives 
the  surviving  image  of  the  anterior  sensation — It  negatives  the  image 
only  as  being  a  contemporary  sensation — The  ordinary  hallucinatory 
process  is  checked  in  one  point  only — The  surviving  image  appears 
as  a  sensation  which  is  not  present — Causes  of  its  apparent  recoil — 
Every  image  occupies  a  fragment  of  duration  and  has  two  extremities, 


xxiv  CONTENTS. 

PAGE- 

one  anterior  and  one  posterior — Circumstances  casting  it  back  into 
the  past — Circumstances  projecting  it  into  the  future — Examples — 
Successive  displacements  and  apparant  wanderings  of  the  image  prior 
to  situating  itself  at  a  greater  or  less  distance  in  the  past  or  future — 
It  becomes  situated  by  intercalation  and  enclosure 238 

VII.  Last  stage  of  rectification — Examples — The  image  then  appears  as  a 
pure  present  image — Representations,  images,  conceptions,  and  ideas 
strictly  so  called— Cases  in  which  they  are  blunted  and  deprived  of 
individual  peculiarities — In  this  case  they  cannot  become  situated 
either  in  the  past,  the  present,  or  the  future — Cases  in  which  they  are 
precise  and  provided  with  individual  peculiarities — Picturesque  or 
poetical  vision — In  this  case,  they  are  promptly  excluded  from  their 
apparent  place  in  the  present,  the  past,  or  the  future — In  both  cases,  i 
the  complete  repression  is  immediate  or  prompt — It  is  the  common 
result  of  the  present  sensation,  of  connected  recollections,  and  ordinary 
previsions 242 

VIII.  Psychological  illusion  as  to  consciousness — We  are  inclined  to  take 
the  knowledge  of  our  present  state  for  a  simple  and  spiritual  act  of 
mind — The  representation,  conception,  or  idea,  recognized  as  such,  is 
but  one  and  the  same  fact  at  two  periods,  in  the  state  of  illusion  and 
in  that  of  repressed  illusion — Common  process  by  which  our  different 
kinds  of  cognitions  are  built  up 247 


BOOK  II. 

THE   KNOWLEDGE   OF   BODIES. 


CHAPTER   I 

EXTERNAL   PERCEPTION   AND  THE  IDEAS   OF   WHICH  THE  IDEA  OF   BODY  IS 

COMPOSED. 

I.  General  character  of  external  perception — It  is  a  true  hallucination — 
The  proofs  in  detail — Its  first  phase  is  a  sensation,  and  this  sensation 
is  in  itself  sufficient  to  excite  the  semblance  of  an  external  body  present 
or  absent — After  perception,  there  is  within  us,  together  with  the 
image  of  the  sensation  experienced,  a  semblance  of  the  object  per- 
ceived, and  this  representation  tends  to  become  hallucinatory — In 
many  instances  the  apparent  object  differs  from  the  real  object — Three 
marks  of  the  semblance — Whether  confounded  or  not,  in  whole  or  in 
part,  with  the  real  object,  it  always  follows  the  sensation  ....  250 

II.  In  what  the  semblance  consists — It  comprises,  among  other  elements, 
the  affirmative  conception  of  a  thing  possessed  of  properties — Analysis 


CONTENTS.  xxv 

PACK 

of  this  conception,  notion,  or  idea — A  thing  is  nothing  more  than  the 
aggregate  of  its  properties — A  substance  is  nothing  more  than  an 
aggregate  of  subsisting  properties — A  body  is  nothing  more  than  a 
cluster  of  sensible  properties 255 

[II.  Sensible  properties  of  bodies — Bodies  as  odorous,  sapid,  sonorous,  col- 
ored, hot,  or  cold — All  we  understand  by  these  properties  is  the  power 
of  exciting  in  us  some  particular  land  of  sensation — Bodies  as  solid  or 
resisting — Stuart  Mill's  analysis  —  Primitively,  resistance  is  nothing 
more  to  us  than  the  power  of  arresting  a  commenced  series  of  muscu- 
lar sensations — Bodies  as  polished,  rough,  pungent,  smooth,  hard,  soft, 
sticky,  damp — All  we  understand  by  these  properties  is  the  power  of 
exciting  some  particular  mode  or  modification  of  a  sensation  or  of  a 
series  cf  muscular  and  tactile  sensations 255 

IV.  Geometrical  and  mechanical  properties  of  bodies — Extension,  figure, 
situation,  mobility — These  notions  combined  with  that  of  resistance 
form  the  essential  part  of  the  notion  of  body — They  are  compounds 
whose  elements  are  notions  of  distance — Bain's  analysis — A  muscular 
sensation  more  or  less  intense  gives  us  the  notion  of  resistance — A 
longer  or  shorter  series  of  muscular  sensations  gives  us  the  notion  of 
greater  or  less  distance — Notion  of  distance  in  one  direction  or  notion 
of  linear  extension — Notion  of  distance  in  more  than  one  direction,  or 
notion  of  extension  of  surface  and  volume — Notion  of  position — No- 
tion of  form — An  entire  series  of  muscular  sensations  may  be  ex- 
hausted in  a  greater  or  less  time — Notion  of  velocity — Double  sen- 
sible measure  of  the  amplitude  of  the  same  movement  effected  by  the 
same  limb — Final  notion  of  the  transit  effected  or  of  the  space  passed 
through — Mill's  theory — To  what  the  notion  of  empty  space  traversed 
and  of  continuous  solid  extension  are  reducible — All  the  properties 
of  bodies  are  reducible  to  the  power  of  exciting  sensations  .  .  .  257 

TT.  Analysis  of  the  word  power — It  signifies  that  certain  sensations  are 
possible  under  certain  conditions  and  necessary  under  certain  condi- 
tions— Every  property  of  a  body  is  reducible  to  the  possibility  of  a  cer- 
tain sensation  under  certain  conditions  and  to  the  necessity  of  the 
same  sensation  under  the  same  conditions  with  a  complementary  one 
added — Confirmation  of  this  paradox — These  possibilities  and  neces- 
sities are  lasting  and  independent — These  two  properties  are  the  es- 
sential characters  of  substance — By  degrees,  they  come  into  opposition 
to  transient  and  dependent  sensations,  and  seem  to  be  data  of  a  dis- 
tinct kind  and  of  a  higher  importance — Development  of  this  theory  by 
Stuart  Mill 264 

VI.  Addition  to  the  theory — Bodies  are  not  only  permanent  possibilities 
of  sensation,  but  aho  permanent  necessities  of  sensation — In  this  re- 
spect, they  are  forces — What  a  body  is  with  respect  to  us — What  a 
body  is  with  respect  to  another  body — Three  groups  of  properties  or 
powers  in  a  body — These  powers  are  otherwise  never  defined  than  by 
their  relation  to  the  events  of  the  sentient  subject,  of  the  body  itself, 


xxvi  CONTENTS. 

PAGE 

or  of  another  body — Among  these  powers  there  are  some  to  which  the 
others  are  reducible — Among  these  events,  there  is  one,  motion,  which 
may  be  substituted  for  the  others — Scientific  Idea  of  body  as  of  a 
movable  motor —  Scientific  Idea  of  solidity,  vacuum,  line,  surface, 
volume,  force,  defined  with  relation  to  motion — The  elements  of  all 
these  ideas  are  never  anything  more  than  sensations,  and  more  or  less 
elaborate  extracts  from  sensation 274 

VII.  Correction  applied  to  theory — Bodies  are  not  only  permanent  possi- 
bilities and  necessities  of  sensation — Process  by  which  we  attribute  to 
them  motion — Analogies  and  differences  between  this  process  and  the 
process  by  which  we  attribute  to  animated  bodies  sensations,  images, 
ideas,  and  volitions  similar  to  our  own 278 

VIII.  Summary — Materials  by  whose  assemblage  the  notion  or  conception 
of  a  body  is  formed — Animal  portion  of  this  conception — Human  por- 
tion of  this  conception — Employment  of  names — Intervention  of 
metaphysical  illusion — First  elements  of  the  hallucinatory  semblance  282 


CHAPTER  II. 

EXTERNAL  PERCEPTION  AND   THE  EDUCATION   OF  THE  SENSES. 

I.  We  assign  a  locality  to  our  sensations — This  operation  is  distinct  from 
sensations  and  requires  a  certain  lapse  of  time  to  accomplish — Experi- 
ments of  physiologists 285 

II.  Sensations  of  touch  are  not  situated  at  the  spot  in  which  we  place 
them — What  is  produced  there  is,  in  the  normal  state,  a  nervous  dis- 
turbance which  is  one  of  their  antecedents — Illusion  of  persons  who 
have  lost  limbs — Observations  and  experiments  of  Mueller — Diseases 
and  compressions  of  the  nervous  trunk — Sensations  wrongly  localized 
by  paralytic  persons  insensible  to  pain — Sensations  wrongly  localized 
after  autoplastic  operations — Experiments  and  observations  of  Weber 
— Law  governing  localization — We  situate  our  sensation  at  the  spot  in 
which  we  have  been  accustomed  to  meet  with  its  usual  condition  or 
cause 286 

HI.  Consequences — We  situate  our  sensations  of  sound  and  color  beyond 
the  limit  our  body — Examples — Alienation  of  our  sensations  of  color 
— They  seem  to  us  a  property  of  the  colored  bodies — Mechanism  of 
this  alienation — Proof  that  color  is  nothing  more  than  a  sensation  ex- 
cited by  a  state  of  the  retina — Subjective  colors — Subjective  sensation 
of  complementary  colors — Luminous  figures  arising  from  the  com- 
pression of  the  eye — Sensation  of  light  excited  by  the  section  of  the 
optic  nerve — Visual  sensations  produced  by  the  prolonged  or  reflected 
excitation  of  the  visual  centres — Various  applications  of  the  law  gov- 
erning localization  —  Part  of  exploring  touch — Case  in  which  the 
situation  of  the  sensation  remains  vague — Internal  sensations — Case 


CONTENTS. 


in  which  the  places  assigned  to  the  causes  of  two  nervous  disturbances 
is  the  inverse  of  the  places  of  the  disturbances  themselves — Images  are 
inverted  on  the  retina — Two  stages  of  localizing  judgment — Why  it  is 
sensations  of  color  and  sound  go  through  these  two  stages — Why  it  is 
sensations  of  contact,  pressure,  and  taste  go  through  the  first  only — 
Intermediate  positions  of  sensations  of  smell  and  of  heat — Ambiguous 
character  of  sensations  of  smell,  heat,  and  cold  which  seem  to  us  to  be 
partially  sensations  and  partially  properties  of  a  body — Summary — 
The  localizing  judgment  is  always  false — Its  practical  utility  .  .  292 

IV.  Elements  of  the  localizing  judgment — Examples — It  is  composed  of 
tactile  and  muscular  images  or  visual  images — Tactile  and  muscular 
Atlas — We  can  ascertain  its  presence  in  the  case  of  persons  born  blind 
— Case  in  which  we  can  ascertain  its  presence  in  ourselves — Examples 
— How  this  tactile  and  muscular  chart  performs  its  functions — It  is 
primitive — Visual  Atlas — It  is  ulterior — The  localization  of  a  sensa- 
tion is  effected  by  the  adjunction  of  the  visual  or  tactile  and  muscular 
images  attached  to  the  sensation — In  the  case  of  instinct,  this  adjunc- 
tion is  spontaneous — \Vith  man,  it  is  an  acquisition  of  experience  .  302 

V.  Differences  of  the  two  Atlases — Spontaneous  formation  of  the  tactile 
and  muscular  atlas — Derived  formation  of  the  visual  atlas — Primitive 
localization  of  visual  sensations — Crude  sensations  of  the  retina — Wrhat 
is  added  to  them  by  the  education  of  the  eye — Observations  made  on 
persons  born  blind  and  restored  to  sight  by  an  operation — Cases 
recorded  by  Cheselden,  Ware,  Home,  Wardrop,  and  Nunneley  — 
To  the  retinal  and  muscular  sensations  of  the  eye  is  added  the  image 
of  the  muscular  sensations  of  transport  and  locomotion  of  the  limbs 
and  whole  body — This  association  is  an  effect  of  experience — Opinion 
of  Helmholtz — The  retinal  and  muscular  sensations  of  the  eye  become 
abbreviatory  signs — Analogy  between  these  sensations  and  names — 
They  are,  like  names,  substitutes  of  images — Usually,  these  images 
remain  in  a  latent  state  and  cannot  be  distinguished  by  consciousness 
— Comparative  process  by  which  we  estimate  great  distances — We 
then  compare  signs  only  305 

VI.  First  notion  of  visible  extension — A  very  short  series  of  muscular  and 
retinal  sensations  of  the  eye  is  the  substitute  of  a  very  long  series  of 
tactile  and  muscular  sensations  of  the  body  and  limbs — Manner  in 
which  persons  born  blind  imagine  extension — How  is  it  that  we  be- 
lieve that  we  perceive  by  sight  a  great  number  of  distant  and  co-exist- 
ing points — The  visual  atlas  is  an  abbreviatory  summary  of  the  tactile 
and  muscular  atlas — Greater  convenience  and  almost  exclusive  em- 
ployment of  the  visual  atlas — Circumstances  in  which  the  tactile  and 
muscular  atlas  is  still  employed — It  remains  atrophied  and  rudimen- 
tary, through  the  predominance  of  the  other — Case  in  which  the  other 
cannot  develop  itself — Perfection  of  touch  in  blind  persons — Instances    319 

VII.  Consequences  of  the  situation  our  sensations  appear  to  have — They 
appear  extended  and  continuous — Consequently,  the  bodies  which  we 


xxviii  CONTENTS. 

PAGE 

know  by  means  of  them  appear  extended  and  continuous — How  far 
this  belief  is  misleading — The  idea  of  extension  is  not  innate  but  ac- 
quired— Idea  of  our  body — Corporal  enclosure  of  the  Ego — Idea  of  an 
external  body — We  conceive  it,  with  reference  to  our  localized  sensa- 
tions, as  a  thing  beyond  it :  and,  with  reference  to  our  body,  as  a 
thing  without  it — Projection  of  sensations  of  sight  and  hearing  into 
this  outer  world — Their  definitive  alienation — Completion  of  the  in- 
ternal semblance  which  at  present  constitutes  for  us  an  external  per- 
ception— Why  it  appears  as  other  than  ourselves,  and  without  us  .  327 

VIII.  How  far  this  hallucination  is  true  in  the  normal  state — Our  illusion 
is  equivalent  to  a  cognition — What  there  is  of  truth  in  the  localizing 
judgment — At  the  spot  in  which  the  sensations  of  the  first  group  ap- 
pear situated  is  found  situated  the  starting  point  of  the  nervous  dis- 
turbance— At  the  spot  in  which  the  sensations  of  the  second  group  ap- 
pear situated  is  found  situated  the  starting  point  of  the  undulation  of 
air  or  ether — What  there  is  of  truth  in  the  external  perception — To 
the  differences  which  distinguish  the  sensations  of  the  second  group 
correspond  differences  in  the  type  of  the  undulations  and  in  the  char- 
acters of  their  starting  points — To  the  corporal  substance  we  pro- 
nounce permanent  there  correspond  a  permanent  possibility  and  ne- 
cessity of  sensations,  and,  in  general,  of  events — Every  external  per- 
ception is  reduced  to  the  assertion  of  a  general  fact  conceived  with  its 
conditions — Usual  accordance  of  the  real  and  mental  law — General 
adaptation  of  the  internal  order  to  the  external  order — Spontaneous 
establishment,  progressive  perfection,  very  simple  mechanism  of  this 
adaptation 331 


BOOK  III. 

THE   KNOWLEDGE   OF   MIND. 


CHAPTER   I. 

THE  KNOWLEDGE  OF  MIND. 

I.  Part  of  the  Idea  of  Self  in  mental  life — Its  almost  incessant  presence 
— The  Ego  compared  with  its  events 338 

II.  Ideas  of  which  the  Idea  of  the  Ego  is  composed — Among  other  ideas  it 
comprises  that  of  a  permanent  being  connected  with  a  certain  organized 
bocjy — What  we  mean  by  this  connection — More  precise  ideas  of 
which  the  Idea  of  the  Ego  is  composed — Idea  of  a  group  of  capacities 
or  faculties 339 


CONTENTS.  xxbc 

PAOK 

III.  What  we  understand  by  the  words  capacity  and  faculty — They  only 
denote  the  possibility  of  certain  events  under  certain  conditions  and 
the  necessity  of  the  same  events  under  the  same  conditions,  with  the 
addition  of  a  complementary  one — These  possibilities  and  necessities 
are  permanent — Capital  importance  which  we  attach  to  them — Meta- 
physical illusion  which  their  name  excites — The  only  real  elements  of 
our  being  are  our  events 340 

IV.  The  distinctive  character  common  to  all  these  events  is  to  appear  as 
internal — Examples — Mechanism  of  the   rectification — Every  repre- 
sentation, conception,  or  idea,  at  its  second  moment,  is  compelled  to 
appear  as  internal — Our  emotions  and  volitions  are  but  the  affective 
and  active  side  of  our  ideas — Hence  it  follows  that  they  also  must 
appear  as  internal — The  sensations  which  we  localize  in  our  bodies  ap- 
pear as  internal — The  sensations  which  we  localize  outside  our  bodies 
appear  as  events  foreign  to  us,  or  as  properties  of  bodies  foreign  to  us.    342 

V.  Our  past  as  well  as  our  present  events  appear  internal — The  series 
of  these  events  appears  as  a  chain — Mechanism  of  memory  which  binds 
them  together  link  by  link — By  the  law  of  the  revival  of  images,  the 
image  of  one  of  our  events  calls  up  those  of  the  preceding  and  follow- 
ing one — Abbreviatory  process  by  which  we  quickly  ascend  or  descend 
long  distances  in  the  whole  series — Examples — Prominent  points  in 
our  past  life — We  leap  from  prominence  to  prominence — Effect  of 
this  rapid  survey — Disengagement  of  a  character  common  to  all  the 
successive  elements  of  the  series — Idea  of  a  stable  -within — This  idea 
is  the  idea  of  Self — Completion  of  this  idea  by  that  of  permanent  fac- 
ulties and  capacities — Final  opposition  of  the  Ego  and  its  events     .       345 

VI.  To  what  real  compound  the  idea  of  Self  actually  corresponds — It  is 
the  product  of  a  long  and  complex  elaboration — Preliminary  opera- 
tions required  to  form  it — It  is,  therefore,  susceptible  of  error — Various 
classes  of  errors  with  respect  to  self — Case  in  which  external  events 
are  introduced  into  the  idea  of  self — Various  examples — Starting 
point  of  the  illusion — In  novelists — In  uncultivated  minds — In  dreams 
— With  madmen — In  hypnotism — Case  in  which  events  appertaining 
to  self  are  attributed  to  another — formal  alienation  of  sensations  of 
sound  and  color — Psychical  hallucinations — Intellectual  conversations 
of  mystics — Story  of  Blake — Other  examples — Starting  point  and  pro- 
gress of  the  illusion — Passage  from  the  psychical  to  the  sensorial  hal- 
lucination— Case  in  which  the  whole  series  of  our  past,  present,  and 
possible  events  is  replaced  by  an  external  series — Starting  point  of  the 
illusion — Suggestions  in  hypnotism — Experiments  of  Drs.  Tuke  and 
Elliotson — Examples  among  monomaniacs — Patients  persuaded  that 
they  are  some  person  other  than  themselves,  that  they  are  changed  into 
animals  or  into  inanimate  bodies,  that  they  are  dead — Analogous  be- 
liefs in  dreams — Mechanism  of  the  idea  of  self  in  the  normal  state — 
Mechanism  of  the  idea  of  self  in  the  abnormal  state — Analogy  be- 
tween the  mental  and  the  vital  process 349 


xxx  CONTENTS. 

PAOK 

VII.  General  veracity  of  recollection — Given  the  mechanism  of  recollection 
its  play  is  usually  sure — To  the  clear  and  circumscribed  present  image, 
there  almost  invariably  corresponds  an  antecedent  sensation  of  which 
the  image  is  the  remnant — To  the  apparent  position  of  the  driven 
back  image  there  almost  invariably  corresponds  the  real  position  of 
the  antecedent  sensation — General  veracity  of  the  notion  we  have  of  our 
faculties — Incessant  experience  controls,  rectifies,  and  consolidates  it 
— Cohesion  of  its  elements — Exceptional  circumstances  must  occur  in 
order  to  disjoin  these  elements  or  to  insert  foreign  ones  among  them 
— General  reason  for  the  agreement  of  our  thoughts  and  things  .  .  360 

VIII.  How,  from  the  idea  of  our  own  mind,  we  form  the  fdea  of  other  minds 
— Analogy  of  other  living  bodies  and  our  own — This  analogy  suggests 
to  us  by  association  the  idea  of  a  mind  similar  to  our  own — Various, 
numerous,  and  constant  verification  of  this  spontaneous  induction.  363 

IX.  General  summary  and  connected  view — In  all  the  preceding  opera- 
tions, an  image  or  group  of  images  is  consolidated  with  a  sensation  or 
a  group  of  sensations,  with  an  image  or  a  group  of  images,  by  virtue 
of  the  laws  of  the  revival  and  association  of  images — Increasing 
complication  of  the  mental  compound  —  Enormous  complication 
of  the  compound  which  constitutes  the  idea  of  an  individual  — 
Every  mental  compound  is  a  couple  and,  in  this  respect,  a  cog- 
nition— When  the  first  term  of  the  couple  is  repeated  by  the  pres- 
ent sensation,  the  second  term  becomes  a  prevision — Mechanism  of 
the  prevision  and  projection  of  the  second  term  into  the  future — In 
the  majority  of  instances,  our  prevision  agrees  with  the  foreseen  event 
— Usual  correspondence  of  the  mental  with  the  real  law — Two  states 
of  the  mental  couple — It  acts  before  being  distinguished — Opposition 
of  animal  to  human  thought — Passage  from  the  first  to  the  second — 
After  ideas  of  individual  things,  rise  ideas  of  general  things  .  .  .  365 


./ 


CONTENTS.  xxxi 


BOOK  IV. 

THE   KNOWLEDGE   OF   GENERAL  THINGS. 
CHAPTER   I. 

OF   GENERAL   CHARACTERS   AND   GENERAL   IDEAS.  PAGE 

General  characters  —  Examples  —  They  are  the  object  of  general 
ideas 371 

§  i.   General  Ideas  which  are  Copies. 

I.  Part  of  general  characters  in  nature — A  group  of  general  characters 
common  to  all  the  moments  of  a  series  of  events  constitutes  the  indi- 
vidual— A  group  of  general  characters  common  to  many  individuals 
constitutes  the  class — General  characters  are  the  fixed  and  uniform  por- 
tion of  existence — They  are  not  pure  conceptions  or  fictions  of  our 
mind — Their  effectiveness  in  nature — They  are  more  or  less  general — 
The  more  general  they  are,  the  more  abstract  they  are 372 

II.  To  these  general  extracts,  general  and  abstract  ideas  correspond  in 
our  minds — These  ideas  are  names  usually  accompanied  by  a  vague  sen- 
sible representation — Examples — The  sensible   representation  is   a 
residue  of  many  blunted  and  confounded  recollections — The  name  is 
a  significant  sound,  that  is  to  say  a  sound  connected  with  that  which 
all  the  sensible  perceptions  and  representations  of  the  individuals  of 
the  class  have  in  common,  and  connected  with  that  alone — In  this 
respect  it  is  the  mental  representative  of  their  common  portion  and  be- 
comes a  general  idea — Mechanism  of  this  exclusive  connection — Ob- 
servations on  children — Analogy  of  infantile  and  scientific  invention 
— In  what  human  intelligence  is  distinguished  from  animal  intelli- 
gence— How,   in   the   child,   transmitted  names   become   significant 
words — Indications  furnished  by  its  barbarisms — Observations  of  Dr. 
Lieber — The  child  receives  words,  but  creates  their  meanings     .     .       376 

III.  Gradual  adaptation  of  general  ideas  to  things — Scientific  research — 
To  the  general  characters  whose  group  constitutes  a  class  we  add 
others — This  addition  has  no  limit — Corrections  afforded  by  these  ad- 
ditions to  the  general  idea — Instances  in  zoology  and  chemistry — Per- 
fectionment  of  our  classifications 382 

IV.  General  characters  appertaining  to  the  elements  of  the  classified  indi- 
viduals— Idea  of  the  leaf  in  botany — Idea  of  the  anatomical  plan  in 
zoology — Idea  of  electric  action — Idea  of  gravitation — Disengagement 


;xii  CONTENTS. 

PAGE 

of  the  most  universal  and  most  stable  characters — Retrenchment  of 
accessory  and  transient  characters — Summary — The  general  idea  is 
adjusted  to  its  object,  first  by  addition,  then  by  subtraction  .  .  .  385 

§  2.   General  Ideas  which  are  Models. 

I.  General  Ideas  whose  objects  are  possible  only — We  construct  such 
ideas — Ideas  of  Arithmetic — Notion  of  Unity — The  property  of  being 
a  unit  is  nothing  more  than  the  aptitude  of  entering  as  an  element 
into  a  collection — All  facts  or  individuals  present  this  property — We 
isolate  it  by  means  of  a  sign  which  becomes  its  mental  representative — 
Successive  inventions  of  different  kinds  of  signs  to  represent  the  series 
of  abstract  units — First  forms  of  calculation — The  ten  fingers — Peb- 
bles— Addition  and  subtraction  by  means  of  the  fingers  and  pebbles 
— Names  of  number,  substitutes  for  fingers  and  pebbles — Convenience, 
small  number  and  simple  combinations  of  these  new  substitutes — 
Final  substitutes,  ciphers — They  are  the  most  abbreviatory  of  all — 
We  thus  form  collections  of  mental  units  without  thinking  of  adapting 
them  to  collections  of  real  units — Subsequently  and  through  experi- 
ence, every  collection  of  real  units  finds  itself  adapted  to  a  collection 
of  mental  units — Examples — Our  numbers  are  preliminary  outlines.  388 

II.  All  the  general  ideas  we  construct  are  preliminary  outlines — Ideas  of 
geometry  —  Notions  of  the  surface,  the  line,  and  the  point — Their 
origin — The  surface  is  the  limit  of  the  sensible  body,  the  line  is  the 
limit  of  the  surface,  the  point  is  the  limit  of  the  line — Convenient  sym- 
bols by  which  we  represent  these  general  characters — Surface  of  the 
board  or  paper,  lines  and  points  in  ink  or  chalk— Analogy  between 
these  substitutes  and  the  fingers  or  pebbles  in  arithmetic — Last  gen- 
eral idea  introduced  into  geometry,  the  idea  of  motion — Its  origin — 
New  aspect  it  gives  to  the  primary  ideas  of  geometry — The  line  is  the 
continuous  series  of  the  successive  positions  of  the  point  in  motion — 
The  surface  is  the  continuous  series  of  the  successive  positions  of  the 
line  in  motion — The  solid  is  the  continuous  series  of  the  successive 
positions  of  the  surface  in  motion — If  for  the  point,  line  and  surface, 
we  substitute  their  symbols,  these  constructions  become  sensible — 
Other  constructions — The  straight  line — The  broken  line — The  curved 
line — The  angle — The  right  angle — The  perpendicular — The  polygon 
— The  circumference — The  plane — The  three  solids  of  revolution — 
The  sections  of  the  cone — Indefinite  number  of  these  constructions — 
To  the  most  general  of  these  mental  constructions  there  are  real  con- 
structions which  correspond — There  are  in  nature,  surfaces,  lines,  and 
points,  at  least  so  far  as  our  senses  are  concerned — There  are  in 
nature,  surfaces,  lines,  and  points  in  motion — To  the  least  general  of 
these  constructions  there  are  real  constructions  which  approximately 
correspond — Why  this  correspondence  is  approximate  only — Exam- 
ples— The  real  construction  is  more  complex  than  the  mental  con- 


CONTENTS.  xxxiii 

PAGE 

struction — The  two  constructions  become  mutually  adjusted  by  the 
complication  of  the  one  and  the  simplification  of  the  other — Utility  of 
preliminary  outlines 393 

III.  Ideas  of  mechanics — Notions  of  rest,  motion,  velocity,  force,  mass — 
Their  origin  and  their  formation — Lines,  ciphers,  and   names   are 
their  symbols — Diversity  and  indefinite  number  of  the  compounds 
constructed  with  these  elements — To  the  most  simple  of  these  mental 
constructions  there  are  real  constructions  which  correspond — Tenden- 
cies of  bodies  at  rest  or  possessed  of  a  uniform  rectilinear  motion  to 
persevere  indefinitely  in  their  state — To  such  of  these  mental  con- 
structions as  are  less  simple  there  are  also  certain  real  constructions 
which  correspond — Hypothesis  of  uniformly  accelerated  velocity  ;  case 
of  heavy  bodies  which  fall — A  movable  body  acted  on  by  a  uniform 
rectilinear  movement  and  by  another  movement  wh6se  velocity  is 
uniformly  accelerated  ;  case  of  the  planets — How  preliminary  out- 
lines must  be  constructed  to  have  a  chance  of  agreeing  with  things — 
Three  conditions — Their  elements  must  be  fashioned  in  accordance 
with  the  elements  of  things — Their  elements  must  be  the  most  general 
possible — Their  elements  must  be  combined  as  simply  as  possible.        397 

IV.  Other  mental  constructions — We  may  form  such  for  all  classes  of  ob- 
jects— Physical  and  Chemical  hypothesis — Among  these  outlines  there 
ldre  some  to  which  we  are  desirous  that  things  should  conform — Men- 
tal Construction  of  the  Useful,  the  Beautiful,  and  the  Good — These 
outlines,  so  constructed,  become  springs  of  action 401 


CHAPTER  II. 

THE  COUPLES   OF   GENERAL  CHARACTERS  AND   GENERAL   PROPOSITIONS. 

I.  General  characters  form  couples — Two  general  characters  coupled  to- 
gether form  a  law — To  conceive  a  law,  is  mentally  to  enounce  a  gen- 
eral proposition .  .  403 

II.  Examples  of  these  coupled  characters — Practical  utility  of  their  connec- 
tions— These  connections  are  of  various  kinds — Unilateral  or  simple 
connections — Bilateral  or  double  connections — The  two  characters 
may  be  simultaneous — They  may  be  successive — Antecedent  and  con- 
sequent— Frequency  of  this  last  case — The  antecedent  then  takes  the 
name  of  cause 403 

III.  In  what  the  connection  consists — Stuart  Mill's  analysis — The  word 
Cause  does  not  denote  any  secret  and  mysterious  virtue  comprised  in 
the  first  character — Its  precise  meaning — Given  the  first  character, 
that  is  enough  for  the  second  to  be  also  given — There  is  nothing 
strange  in  general  characters  having,  like  particular  facts,  antecedents, 


CONTENTS. 


companions,  and  consequents — The  difficulty  is,  to  isolate  the  general 
characters — Two  artifices  of  method  for  evading  the  difficulty — Two 
kinds  of  Laws 406 

§   i.  Laws  concerning  Real  Things. 

I.  First  general  judgments  of  the  infant — Mechanism  of  their  formation — 
Passage  from  animal  judgment  to  human  judgment — General  judgments 
become  multiplied — They  are  the  summary  and  measure  of  anterior 
experience — How  subsequent  experience  rectifies  them — Gradual  adap- 
tation of  our  couples  of  mental  characters  to  the  couples  of  real  char- 
acters— We  believe  at  present  that  every  general  character  is  connec- 
ted with  another — Provisional  admission  of  this  hypothesis — It  is  the 
principle  of  Scientific  Induction 409 

II.  Various  methods  of  Scientific  Induction — When  a  known  character  is 
given,  this  is  sufficient  to  give  another  character  which  was  unknown 
— Search  for  the  unknown  character  from  this  indication — Method  of 
Agreement — Method  of  Difference  —  Method  of  concomitant  varia- 
tions— Various  examples — All  these  methods  are  processes  of  elim- 
ination —  They  are  efficient  in  proportion  to  the  magnitude  of 
the  eliminations  they  effect — When  the  elimination  is  complete, 
the  residue  contains  the  unknown  character  of  which  we  are  in 
search — Complementary  Method  of  Deduction — Example — Theory  of 
Herschel  and  Mill — Example  of  these  various  methods  in  the  inquiry 
into  the  antecedent  of  dew 412 

§  2.  Laws  concerning  Possible  Things. 

I.  Lengthiness  of  the  processes  described  above — Laws  thus  discovered 
are  probable  only  beyond  the  circle  of  our  experience — The  most  gen- 
eral are  last  discovered 426 

II.  Propositions  concerning  possible  things  are  different  in  character — 
Universal  truth  of  mathematical  theories — We  cannot  conceive  an  in- 
stance in  which  these  propositions  are  false — The  most  general  are 
formed  first — Among  the  most  general,  there  are  some  called  axioms, 
on  which  the  others  depend,  and  which  we  admit  without  demonstra- 
tion   426 

III.  Two  kinds  of  proof  for  the  theorems  of  the  so-called  Sciences  of  Con- 
struction— Example — Difference  of  the  two  methods  of  proof — Axioms 
are  unproved  theorems — They  are  analytical  propositions — We  either 
dispense  with  their  demonstration  because  the  analysis  required  is 
very  easy,  or  evade  their  demonstration  because  the  analysis  required 
is  very  difficult — Axioms  of  identity  and  contradiction — Axiom  of  the 
alternative — Analysis  demonstrating  it — Latent  ideas  contained  in  the 
two  members  of  the  proposition  expressing  it — These  undisengaged 
ideas  determine  our  conviction — There  are  latent  and  proving  ideas 
of  the  same  kind  in  the  terms  of  the  other  axioms 428 


CONTENTS.  xxxv 

PAGB 

IV.  Mathematical  axioms— Axioms  as  to  equal  quantities  augmented  or 
diminished  by  equal  quantities — Experimental  and  inductive  proof — 
Analytical  and  deductive  proof — Case  of  artificial  magnitudes  or  col- 
lections of  natural  units — Two  of  these  collections  are  equal  when 
they  contain  the  same  number  of  units — Case  of  natural  magnitudes 
or  collections  of  artificial  units — Two  of  these  magnitudes  are  equal 
when  they  coincide  and  are  confounded  in  one  same  magnitude — 
Disengagement  of  the  idea  of  identity  included  and  latent  in  the  idea 
of  equality 432 

V.  Principal  geometrical  axioms — Axioms  concerning  the  straight  line 
— Definition  of  the  straight  line — Propositions  derived  from  it — Two 
straight  lines'  having  two  points  in  common  coincide  in  all  their  in- 
termediate, and  in  all  their  ulterior  extent — Axioms  relating  to  paral- 
lel lines — Definition  of  parallel  lines — Propositions  derived  from  it — 
Two  lines  perpendicular  to  the  same  straight  line  are  equi-distant 
throughout — Examination  of  Euclid's  Postulate 438 

VI.  Underlying  mental  process  which  accompanies  the  experience  of  the 
eyes  and  imagination — This  process  consists  in  the  silent  recognition 
of  a  latent  identity — The  experience  of  the  eyes  and  imagination  is 
nothing  more  than  a  preliminary  indication  and  a  subsequent  confirm- 
ation— Its  utility — Case  in  which  this  indication  and  this  confirmation 
are  wanting — Axioms  of  mechanics — Their  late  discovery — Ordinary 
experience  does  not  suggest  them — How  scientific  experience  discov- 
ered them — Opinion  which  places  them  among  truths  of  experience — 
Many  of  them  are,  in  addition  to  this,  analytical  propositions — Prin- 
ciple of  Inertia — Exact  enunciation  of  the  axiom — The  difference  of 
place  and  moment  is,  by  hypothesis,  without  influence  or  of  no  effect 
— Limits  of  the  axiom  thus  extended  and  demonstrated — Principle  of 
the  parallelogram  of  velocities  and  of  forces — Exact  enunciation  of 
the  axiom — The  co-existence  of  a  second  movement  in  the  same  mov- 
able body  is,  by  hypothesis,  without  influence  or  of  no  effect — Passage 
from  the  idea  of  velocity  to  that  of  force 446 

VII.  Axioms  relating  to  Time  and  Space — Mathematical  Idea  of  Time  and 
Space — Every  determinate  duration  or  extension  has  something  be- 
yond it — Analysis  of  this  conception — Every  determinate  magnitude, 
artificial  or  natural,  has  in  the  same  way  something  beyond  it,  and  is 
found   comprised    in    an    infinite    series — Examples — A    number — A 
straight  line — Demonstration  of  the  axiom — It  is  an  analytical  propo- 
sition— Every  addition  effected  implies  an   addition  that  may  be  ef- 
fected— Discovery  of  the  ideas  of  identity  and  indifference  included 
and  latent  in  the  terms  of  the  axiom — All  the  axioms  we  have  exam- 
ined are  analytical  propositions  more  or  less  disguised 453 

VIII.  Importance  of  the  question — Origin,  formation,  and  value  of  axioms 
and  the  theories  derived  from  them — Opinion  of  Kant — Opinion  of 
Stuart  Mill — Conclusions  of  Kant  and  Stuart  Mill  on  the  range  of  the 
human  mind  and  on  the  nature  of  things — Proposed  theory— What  it 


CONTENTS. 

PAGE 

concedes  and  denies  in  the  two  preceding  theories — There  is  an  in- 
trinsic and  necessary  connection  between  the  two  ideas  whose  couple 
forms  a  theorem — There  is  an  intrinsic  and  necessary  connection  be- 
tween the  two  general  characters  which  correspond  to  these  two  ideas 
— It  remains  for  us  to  know  whether  these  general  characters  are  actu- 
ally met  with  in  things — They  are  met  with  wherever  the  theorems 
are  applicable 456 


CHAPTER   III. 

THE  CONNECTION   OF   GENERAL  CHARACTERS,   OR  THE  EXPLANATORY   REASON 

OF  THINGS. 

§  i.  Nature  of  the  Explanatory  Intermediate. 

I.  In  many  cases  the  connection  of  two  data  is  explained — What  is  asked 
by  the  word  why — Intermediate  and  explanatory  datum  which,  being 
connected  to  the  first  and  the  second,  connects  the  second  to  the  first 
— Premises,  conclusion,  reasoning 462 

II.  Propositions  in  which  the  first  datum  is  an  individual — Examples — In 
this  case  the  intermediate  is  a  character  more  general  than  the  indi- 
vidual and  comprised  in  it — Propositions  in  which  the  first  datum  is 
a  general  thing — This  the  case  with  laws — The  intermediate  is  then 
the  reason  of  the  law — Successive  discoveries  which  have  determined 
the  reason  of  the  fall  of  bodies — Here  again  the  explanatory  inter- 
mediate is  a  more  general  and  more  abstract  character  included  in 
the  first  datum  of  the  law — Present  hypothesis  of  physicists  on  the  ex- 
planatory reason  of  gravitation — Same  conclusion 462 

III.  Laws  in  which  the  explanatory  intermediate  is  a  transient  character 
communicated  to  the  antecedent  by  its  surroundings — Law  connect- 
ing the  sensation  of  sound  with  the  vibration  transmitted  from  an 
external  body — Same  conclusion  as  in  the  preceding  case — The  inter- 
mediate is  then  a  series  of  successive  general  characters  ....  465 

IV.  Laws  in  which  the  intermediate  is  a  sum  of  simultaneous  general 
characters — Of  the  composition  of  causes — Law  of  the  motion  of  a 
planet — Law  in  which  the  first  datum  is  a  sum  of  separable  data — 
Examples  in  arithmetic  and  geometry — In  this  case  the  intermediate 
is  a  general  character  repeated  in  all  the  elements  of  the  first  datum — 
Example  in  zoology — Law  of  the  connection  of  organs — The  inter- 
mediate repeated  in  each  organ  is  the  property  of  being  useful — These 
kinds  of  intermediates  are  the  most  instructive — Summary — The  ex- 
planatory reason  of  a  law  is  a  general  intermediate  character,  simple 
or  multiple,  included  directly  or  indirectly  in  the  first  datum  of  the 
law  .  ,  467 


CONTENTS.  xxxvii 

PAGE 

V.  Of  explanation  and  demonstration — The  first  datum  contains  the  in- 
termediate which  contains  the  second  datum — Hence  three  connected 
propositions — Order  of  these  propositions — In  what  the  scientific 
syllogism  consists 472 

§  2.  Methods  of  finding  the  Explanatory  Intermediate. 

I.  The  position  and  characters  discovered  in  the  intermediate  afford  the 
means  of  finding  it — Method  in  the  sciences  of  construction — Advan- 
tages they  have  over  the  sciences  of  experience — The  intermediate  is 
always  included  in  the  definition  of  the  first  datum  of  the  law — We 
may  always  derive  it  thence  by  analysis — Example,  the  demonstration 
of  axioms — Other  examples — Theorem  of  the  equality  of  the  opposite 
sides  of  the  parallelogram — How  intermediates  enclose  one  another — 
In  what  the  skill  and  labor  of  the  geometrician  consist — Method  he 
follows  in   his   constructions — The  more   complex  compounds  have 
simpler  factors — The  properties  of  these  simpler  factors  are  the  inter- 
mediates by  which  the  more  complex  compounds  possess  their  proper- 
ties— The   last  intermediate  is  always  a  property  of   the   primitive 
factors — This  property  is  the  ultimate  reason  of  the  mathematical  law 
— Place  of  axioms — They  enounce  those  properties  of  the  factors  or 
primitive  elements  which  are  the  simplest  and  most  general  of  all — 
Analysis  must  apply,  then,  to  the  primitive  elements — Primitive  ele- 
ments of  the  line — Discovery  of  a  character  common  to  all  the  elements 
or  points  of  a  line — Definition  of  a  line  by  the  constant  ratio  of  its 
co-ordinates — Analytical  Geometry — Primitive  elements  of  a  magni- 
tude— The  infinitesimal  calculus — In  every  law  enounced  by  a  science 
of  construction,  the  ultimate  reason  of  the  law  is  a  general  character 
included  in  the  elements  of  the  first  datum  of  the  law 474 

II.  Method  in  the  experimental  Sciences — Their  disadvantages — Insuffi- 
ciency of  analysis — Why  we  are  compelled  to  employ  experience  and 
induction — Law  connecting  dew  with  cooling — Included  intermedi- 
ates connecting  the  second  datum  of  this  law  to  the  first — The  method 
of  discovering  the  intermediate  differs,  according  as  it  is  a  question 
of  real  or  mental  compounds,  but  the  connection  of  the  second  datum 
and  of  the  first  is  formed   in   the  same  way — Very  advanced  experi- 
mental sciences — Analogy  of  these  sciences  and  of  the  mathematical 
sciences — Their   most   general   laws   correspond   to   axioms  —  They 
enounce,  like  axioms,  properties  of  primitive  factors — How  far  these 
laws  still  differ  from  axioms — They  are  provisionally  irreducible.     .       482 

III.  Same  arrangement  in  the  less  advanced  experimental  Sciences — Their 
most  general  laws  also  enounce  properties  of  primitive  factors — Sci- 
ences in  which  the  primitive  factors  may  be  observed — Zoology — 
General  characters  of  organs — Cuvier's  law — Geoffroy  Saint-Hilaire's 
law — History — General  characters  of  the  individuals  of  an  epoch,  of  a 
nation,  or  of  a  race — Psychology — General  characters  of  the  elements 
of  knowledge — All  these  general  characters  are  explanatory  interme- 


CONTENTS. 


diates — They  are  the  more  explanatory  in  proportion  as  they  apper- 
tain to  more  general  and  more  simple  primitive  factors — Explanation 
is  at  an  end  when  we  arrive  at  primitive  factors  which  we  can  neither 
observe  nor  conjecture — Present  limits  of  physiology,  physics,  and 
chemistry — Beyond  known  factors  the  simpler  unknown  factors  may 
have  either  different  or  the  same  properties — According  as  one  or  the 
other  of  these  hypotheses  is  true,  the  explanation  has  or  has  not 
limits 487 

IV.  Another  disadvantage  of  the  experimental  Sciences — They  have  to 
answer  to  questions  of  origin — Historical  portion  of  every  experimen- 
tal science — Laplace's  hypothesis — Researches  of  mineralogists  and 
geologists — Darwin's  Ideas — Views  of  historians — General  Theory  of 
Evolution — Gaps — Daily  progress  which  fills  them  up — The  formation 
of  a  compound  is  explained  by  the  properties  of  its  elements  and  by 
the  characters  of  the  antecedent  circumstances — The  explanatory  in- 
termediate is  the  same  in  this  and  in  the  preceding  cases  .  .  .  493 

§  3.  If  every  Fact  or  Law  has  its  Explanatory  Reason. 

I.  Convergence  of  all  the  preceding  conclusions — They  indicate  that,  in 
every  couple  of  actually  connected  events,  there  is  an  explanatory  in- 
termediate which  necessitates  this  connection — At  all  events  we  be- 
lieve that  it  is  so — We  predict,  by  analogy,  the  characters  of  the  inter- 
mediate in  the  cases  in  which  it  is  still  unknown  to  us — Examples — 
We  extend  this  law  by  analogy  to  all  points  of  space  and  all  moments 
of  time 498 

'  II.  Groundwork  of  this  induction — From  our  ignorance  in  certain  cases 
of  the  explanatory  reason,  we  cannot  conclude  that  it  does  not  then 
exist — The  cause  of  our  ignorance  is  known  to  us — The  gaps  of  sci- 
ence are  explained  by  its  conditions — Examples — To  presume  the  ab- 
sence of  the  explanatory  reason  is  a  gratuitous  hypothesis — The  pre- 
sumptions are  in  favor  of  the  presence  of  an  explanatory  reason  of 
which  we  are  ignorant — Other  presumptions  suggested  by  the  exam- 
ple of  the  sciences  of  construction — In  these  sciences,  every  law  has  its 
known  explanatory  reason — The  gaps  of  the  experimental  sciences  are 
caused  by  their  conditions  and  by  the  particular  turn  of  their  method 
— Proof — What  geometry  would  be  if  formed  by  induction — The  gaps 
of  geometry  would  then  be  the  same  as  those  of  physics  or  chemistry — 
The  Sciences  of  Construction  are  a  preliminary  model  of  that  which 
the  experimental  sciences  might  be — Analogy  of  their  arrangements — 
Identity  of  the  materials — The  only  difference  between  our  mental 
and  real  compounds  is,  that  the  first  are  the  more  simple — Employ- 
ment of  mental  compounds  in  order  to  understand  real  compounds — 
Consequences — The  application  of  mathematical  and  mechanical  laws 
is  universal  and  necessary — Refutation  of  Stuart  Mill — All  numbers, 
forms,  movements,  and  forces  of  physical  nature  are  subject  to  neces- 
sary laws — Very  probably,  all  the  physical  changes  in  the  world,  and 


CONTENTS.  xxxix 

PAGE 

probably  all  the  physical  changes  beyond  our  world,  are  reducible  to 
movements  which  have  movements  for  their  conditions — Idea  of  the 
physical  universe  as  a  collection  of  movable  motors  subject  to  the  law 
of  the  Conservation  of  Force 500 

III.  Recapitulation  of  the  inductive  proofs  which  make  us  believe  in  the 
principle  of  the  Explanatory  Reason — Our  natural  inclination  to  ad- 
mit it — Employment  made  of  it  by  scientific  men  for  the  purpose  of 
induction — Opinion  of  Claude  Bernard — Opinion  of  Helmholtz — Ex- 
planation of  this  belief  by  the  innate  structure  of  our  mind — Another 
explanation — Analogy  of  this  principle  and  of  the  axioms  previously 
demonstrated — It  is  probable  that,  like  them,  it  may  be  demonstrated 
by  analysis — Demonstration — Latent  identity  of  the  terms  enouncing 
it — Limits  of  the  axiom  so  demonstrated  and  understood — The  axiom 
of  Cause  is  derived  from  it — Consequences  of  the  axiom  of  explanatory 
reason — The  intervention  of  experience  is  necessary  in  order  that  it 
may  be  applied — Possible  application  of  the  axiom  to  the  problem  of 
existence — General  Summary  of  the  present  psychological  theory  .  .  507 


END  OF  THE  TABLE  OF  CONTENTS. 


LIBRARY 


ON    INTELLIGENCE 


PAET    THE  FiKST. 
THE  ELEMENTS   OF  KNOWLEDGE. 


BOOK     I. 

OF  SIGNS. 

CHAPTER  I. 

OF   SIGNS   IN   GENERAL  AND   OF   SUBSTITUTION. 

I.  IF  we  ascend  the  Arc  de  1'Etoile,  and  look  down  on  the 
Champs  Elysees,  we  see  a  number  of  black  or  variously  colored 
specks  stirring  about  on  the  roadway  or  pavements.  That  is 
all  our  eyes  distinguish.  But  we  know  that  each  of  these  specks 
is  a  living  body,  with  active  limbs,  a  wise  economy  of  organs, 
and  a  thinking  brain  actuated  by  some  project  oh  inward  desire 
—in  short,  is  a  human  being.  The  presence  of  the  specks  has 
indicated  the  presence  of  persons.  The  first  have  been  signs  of 
the  second. 

Associations  of  this  kind  are  continually  being  met  with. — 
At  night  we  look  up  to  the  starry  sky,  and  say  to  ourselves 
that  each  of  these  brilliant  points  is  an  enormous  mass  like  the 
sun. — When  we  walk  in  the  fields  on  an  autumn  evening,  we 
see  the  blue  smoke  rising  calmly  in  the  distance,  and  think  at 
once  of  the  slow  fires  with  which  the  peasants,  are  burning  up 
the  stubble. — We  turn  over  sheets  of  music,  and,  while  the  eye 
follows  the  black  and  white  marks  with  which  the  lines  are  dot- 
ted, we  hear  mentally  the  sounds  they  indicate. — A  sharp  cry 
of  a  particular  tone  comes  from  a  neighboring  room,  and  we  pic- 
ture to  ourselves  the  face  of  a  child,  crying  no  doubt  because 
1 


2  OF  SIGNS.  [BOOK  I. 

he  has  hurt  himself.  The  greater  part  of  our  ordinary  judg- 
ments are  made  up  of  connections  like  these.  When  we  drink 
or  walk,  or  use  our  limbs  for  any  purpose,  we  foresee,  by  means 
of  a  perceived  fact,  a  fact  which  we  do  not  yet  perceive ;  animals 
do  the  same;  according  to  the  color  or  smell  of  an  object,  they 
eat  or  leave  it. — In  all  these  cases  a  present  experience  suggests 
the  idea  of  another  possible  experience ;  from  the  first  we  im- 
agine the  second ;  the  perception  of  an  event,  object,  or  char- 
acter, arouses  the  conception  of  another  event,  object,  or  char- 
acter. When  we  touch  the  first  link  of  the  couple  we  picture  to 
ourselves  the  second  link,  and  the  first  is  the  sign  of  the  second. 

II.  In  this  great  family  of  signs  there  is  one  species  whose 
properties  are  remarkable  ;  these  are  names, 

Let  us  first  consider  proper  names,  which  are  the  easier  to 
study  from  each  one  denoting  some  particular,  precise  thing ; 
as,  for  example,  the  names  Tuileries,  Lord  Palmerston,  Luxem- 
bourg, Notre  Dame,  etc.  These  clearly  belong  to  the  family  we 
have  just  described,  and  each  of  them  is  the  sensible  and  ap- 
parent first  term  of  a  couple.  When  I  hear  the  word  Lord 
Palmerston  pronounced,  or  read  the  fourteen  letters  of  which 
it  is  made  up,  I  form  a  mental  image  of  his  brisk  erect  figure, 
gesticulation,  and  smile,  just  as  I  have  seen  him  in  his  place  in 
Parliament.  Again,  when  I  read  or  hear  the  word  Tuileries,  I 
picture  more  or  less  vaguely,  in  more  or  less  mutilated  forms,  a 
level  garden,  flower-beds  enclosed  with  rails,  marble  statues,  the 
rounded  heads  of  chestnut-trees,  the  fall  and  plume  of  a  foun- 
tain, and  the  rest.  A  short  insignificant  sensation,  acting 
through  our  eyes  or  ears,  has  the  property  of  calling  up  in  us  a 
certain  image,  or  series  of  images,  more  or  less  definite,  and 
the  connection  between  the  first  and  second  terms  of  this  coup- 
le is  so  precise,  that  in  a  hundred  million  instances,  and  for 
two  millions  of  men,  the  first  term  invariably  calls  up  the 
second. 

III.  Suppose  now  that  instead  of  dwelling  on  the  word  Tuil- 
eries, and  calling  up  the  different  images  connected  with  it,  I 
glance  quickly  at  a  phrase  like  this  : — "  There  are  many  public 
gardens  in  Paris,  both  small  and  great,  some  no  bigger  than  a 
drawing-room,  others  as  large  as  a  park,  the  Jardin  des  Plantes, 
the  Luxembourg,  the  Bois  de  Boulogne,  the  Tuileries,  Champs 


CHAP.  I.]  OF  SIGNS  IN  GENERAL.  3 

Elysees,  the  squares,  besides  the  new  parks  which  are  being  laid 
out,  all  very  neat  and  well  looked  after."  I  ask  the  ordinary 
reader  who  has  just  gone  through  this  list  with  ordinary  speed, 
if,  when  his  eye  ran  over  the  word  Tuileries,  he  saw  mentally 
as  before,  some  fragmentary  image,  some  patch  of  blue  sky  ap- 
pearing through  trees,  the  attitude  of  some  statue,  some  vague- 
ly extending  avenue,  the  sparkling  of  water  in  a  basin? — Assur- 
edly not,  his  eye  ran  over  it  too  quickly ;  there  is  a  notable  dif- 
ference between  this  and  the  preceding  operation.  In  the  first, 
the  sign  aroused  pictures  more  or  less  faded  of  the  sensation, 
revivals  more  or  less  enfeebled  of  the  experience ;  in  the  second, 
the  sign  did  not  arouse  them.  In  the  one  case,  the  two  links 
of  the  couple  appear;  in  the  other,  the  first  link  alone  appears. 
Between  these  two  operations  are  an  infinite  number  of  inter- 
mediate states  occupying  the  whole  interval ;  these  states  con- 
nect the  intense  half-sight  with  the  dry  notation,  by  a  series  of 
degradations,  rubbings  out,  and  losses,  which  strip  by  degrees 
the  complete  and  puissant  image,  till  they  leave  us  nothing  but 
a  simple  word. 

This  word  so  reduced  is  not  however  a  lifeless  symbol,  with- 
out trace  of  signification ;  it  is  more  like  the  trunk  of  a  tree, 
stripped  indeed  of  its  leaves  and  branches,  but  capable  of  repro- 
ducing them  ;  we  understand  it  as  we  pass  it,  and  with  whatever 
speed  we  may  pass  it ;  it  does  not  come  to  us  as  a  stranger,  or 
strike  us  as  an  intruder  ;  in  its  long  association  with  the  expe- 
rience and  image  of  the  object,  it  has  contracted  certain  affinities 
and  repugnances  ;  and  in  passing  through  us  carries  with  it  this 
retinue  of  affinities  and  repugnances  ;  however  briefly  we  retain 
the  word,  the  image  to  which  it  corresponds  commences  to 
form ;  the  image  accompanies  the  word  in  a  nascent  state,  and, 
though  not  actually  formed,  acts  on  us  as  if  it  were.  Read,  for 
instance,  a  sentence  like  this: — "  London,  the  capital  of  Eng- 
land, has  several  fine  gardens — Hyde  Park,  Regent's  Park,  and 
the  Tuileries." — We  experience  a  certain  shock  and  surprise; 
we  point  involuntarily  in  two  directions,  towards  Paris  and 
towards  a  far  distant  city.  The  image  of  the  Tuileries  is 
aroused  with  the  Seine  and  quays  beside  it,  and  we  are  arrested, 
when  we  try  to  transport  them  elsewhere.  But  before  the 
image  appeared,  we  experienced  a  resistance  in  the  word  itself, 


4  OF  SIGNS.  [BOOK  I. 

a  resistance  which  was  strengthened  and  renewed  when  the 
image  reappeared.  Prolong  and  vary  the  experiment ;  you 
will  find  in  the  word  a  system  of  tendencies  all  corresponding  to 
those  of  the  image,  all  acquired  by  it  in  its  connection  with  the 
experience  and  the  image,  but  now  spontaneous,  and  acting, 
sometimes  to  connect  it  with,  sometimes  to  sever  it  from,  other 
words  or  groups  of  words,  images  or  groups  of  images,  experi- 
ences or  groups  of  experiences.  In  this  way  the  simple  name 
is  enabled  to  take  the  place  of  the  image  it  arouses,  and  conse- 
quently, of  the  experience  it  recalls  ;  it  performs  their  office  and 
becomes  their  substitute. 

IV.  In  the  case  we  have  considered,  the  obliteration  of 
the  image  forming  the  second  member  of  the  couple  is,  as  gen- 
erally happens  with  proper  names,  gradual  and  involuntary. 
Let  us  consider  another  case,  in  which  we  suddenly  and  volun- 
tarily suppress  it ;  the  reader  will  then  see  the  operation  more 
clearly  set  out. 

My  garden  is  surrounded  by  a  hedge,  and  my  fruit  is  stolen  ; 
I  determine  on  enclosing  it  with  a  wall.  I  get  what  workmen 
I  can  in  the  village — four,  for  instance — and  at  the  end  of  the 
day  I  find  they  have  built  twelve  metres  of  wall.  This  is  not 
fast  enough  ;  I  send  to  the  next  village  for  six  other  workmen, 
and  ask  myself  how  many  metres  a  day  will  be  added  to  the 
wall.  To  find  out  this,  I  no  longer  picture  to  myself  workmen 
with  their  blouses  and  trowels — the  wall  with  its  stones  and 
mortar,  but  replace  my  first  workmen  by  the  figure  four,  the 
first  amount  of  work  by  the  figure  twelve,  the  whole  of  the 
workmen  by  the  figure  ten,  the  unknown  amount  of  work  they 
will  do  by  the  sign  x,  and  write  down  the  following  propor- 
tion : 

12  X  10 
4  :  12  : :  10  x  = =  30. 

4 

Henceforth,  barring  accident  or  drunkenness,  if  the  new  men 
work  like  the  old,  and  all  continue  to  work  together  as  the  first 
four  began,  my  ten  men  will  build  thirty  metres  a  day.  Oper- 
ations of  this  kind  occur  daily,  and  all  practical  calculations  are 
made  in  this  way.  For  the  real  objects  first  imagined,  figures 
are  substituted  which  replace  them  partially ;  they  replace  them 


CHAP.  I.]  OF  SIGNS  IN  GENERAL.  5 

in  the  only  point  of  view  in  which  we  need  consider  them,  that 
is,  in  point  of  number.  This  once  effected,  we  forget  the  ob- 
jects represented ;  they  recede  into  the  background ;  we  only 
consider  the  figures,  we  assemble,  compare,  transpose,  and  ma- 
nipulate them  as  more  convenient  equivalents,  and  the  figure 
we  finally  arrive  at  indicates  the  object,  or  group  of  objects,  at 
which  we  wish  to  arrive. 

Substitution  goes  further  than  this,  and  figures  substituted 
for  things  have  in  turn  letters  substituted  for  them.  After  sev- 
eral similar  calculations,  I  observe  that  in  all  such  cases  the 
proportion  is  written  in  the  same  way,  that  the  first  figure  al- 
ways represents  the  first  workmen  ;  the  second,  their  work;  the 
third,  the  whole  number  of  workmen  ;  the  fourth,  the  unknown 
work ;  and  thus  I  pass  from  arithmetic  to  algebra.  Hence- 
forth I  replace  the  first  figure  by  A,  the  second  by  B,  the  third 
by  C,  and  write  down  as  follows  : — 

BXC. 

A  :  B  :  :  C  :  x  = 

A. 

And  I  see  that,  in  every  such  case,  if  I  want  to  know  the 
amount  of  work  which  will  be  done  by  all  the  workmen,  it  will 
be  sufficient  to  multiply  their  number  by  that  representing  the 
work  done  by  the  first  lot,  and  then  to  divide  the  product  by 
the  number  of  the  workmen  first  employed. 

Instead  of  this  simple  case,  let  us  consider  the  labor  of  an 
analyst  who  writes  equations  by  the  hour.  He  lays  aside  the 
figures,  but  indirectly  he  is  working  on  them,  just  as  an  arith- 
metician lays  aside  the  facts,  but  works  indirectly  on  the  facts. 
He  effaces  figures  from  his  mind  as  the  other  effaces  things. 
Each  of  them  arranges  and  combines  signs,  and  these  signs  are 
substitutes.  The  fact  is,  they  are  not  like  proper  names,  sub- 
stituted for  the  whole  of  the  object  they  represent,  but  merely 
for  a  portion  or  an  aspect  of  such  object.  The  letter  used  in 
algebra  does  not  fully  replace  the  arithmetical  cipher  with  its 
precise  quantity,  but  only  as  regards  its  function  and  place  in 
the  equation  it  enters  into.  The  arithmetical  cipher  does  not 
fully  replace  the  thing  it  stands  for,  with  all  its  qualities  and 
characters,  but  only,  as  regards  quantity  and  number.  Each  re- 
places part  only  of  the  imagined  object,  that  is  to  say,  a  frag- 


6  OF  SIGNS.  [BOOK  I. 

ment — an  extract ;  the  cipher  a  more  complex  extract ;  the  let- 
ter a  less  complex  one,  that  is  to  say,  an  extract  from  the  first 
extract.  But  the  substitution,  though  partial,  is  none  the  less 
actual.  Two  complete  and  infinitely  fertile  sciences  depend 
on  it,  and  derive  their  efficacy  from  it. — The  reader  must  par- 
don me  for  dwelling  on  simple  remarks  like  these.  In  the  for- 
mation of  couples,  such  that  the  first  term  of  each  suggests  the 
second  term ;  and,  in  the  aptitude  of  this  first  term  to  stand, 
wholly  or  partially,  in  place  of  \\\z  second,  so  as  to  acquire,  either 
a  definite  set  of  its  properties,  or  all  those  properties  combined, 
we  have,  I  think,  the  first  germ  of  the  higher  operations  which 
make  up  man's  intelligence ;  we  shall  now  consider  them  in 
detail. 


CHAP.  II.]  SIMPLE  SUBSTITUTION. 


CHAPTER  II. 

OF   GENERAL   IDEAS  AND   SIMPLE   SUBSTITUTION. 

I.  NAMES,  as  we  know,  are  divided  into  proper  and  com- 
mon ;  and  these  are  correctly  distinguished  by  saying  that  the 
first,  as  Caesar,  Tuileries,  Cromwell,  correspond  to  a  single  object ; 
while  the  second,  as  tree,  triangle,  color,  correspond  to  an  indef- 
inite group  of  objects.  These  last  are  the  most  numerous,  and 
the  most  in  use  in  every  individual  mind ;  there  are  thirty  or 
forty  thousand  of  them  in  a  language,  and  they  make  up  of 
themselves  the  whole  dictionary.  Further  than  this,  they  are 
the  most  important ;  by  their  aid  we  make  classifications,  judg- 
ments, and  reasonings,  and  pass,  in  short,  from  crude,  loose  expe- 
rience to  orderly  complete  knowledge.  Let  us  consider  them  at- 
tentively. We  should  attain  a  truth  of  capital  importance,  and 
infinite  in  its  consequences,  could  we  determine,  not  as  gram- 
marians and  logicians,  but  as  psychologists,  their  true  nature 
and  precise  office. 

Like  all  signs,  and  especially  like  all  names,  each  one  is  the 
first  term  of  a  couple,  and  draws  with  it  a  second  term.  But 
this  second  term  has  remarkable  characteristics,  which  distin- 
guish it  from  all  others,  and  give  the  name  peculiar  qualities. 
Logicians  and  grammarians  tell  us  rightly  that  a  common 
name,  like  tree  or  polygon,  is  a  general  or  abstract  name. — It 
is  general  because  it  corresponds  to  a  class  (genus)  or  group  of 
similar  objects ;  the  name  of  tree  to  all  trees,  poplars,  oaks, 
cypress,  birch,  etc.  ;  the  name  of  polygon  to  all  polygons,  tri- 
angles, quadrilaterals,  pentagons,  hexagons,  etc. — It  is  abstract 
because  it  denotes  an  extract,  that  is,  a  portion,  of  an  individual, 
and  a  portion  which  is  found  in  every  individual  of  the  group ; 
the  name  tree  expresses  the  quality  common  to  all  kinds  of 
trees,  poplars,  oaks,  cypress,  birch,  etc. ;  that  of  polygons  rep- 
resents the  quality  common  to  all  sorts  of  polygons,  triangles, 


g  OF  SIGNS.  [BOOK  I. 

quadrilaterals,  pentagons,  hexagons,  etc. — We  see  the  connec- 
tion between  these  two  characters  of  a  name ;  it  is  general  be- 
cause it  is  abstract ;  it  corresponds  to  a  whole  class,  because  the 
object  it  denotes,  being  but  a  fragment,  may  be  found  in  all  the 
individuals  of  the  class,  which,  similar  in  this  point,  remain, 
nevertheless,  dissimilar  in  other  points.  Here  we  have  a  couple 
of  a  new  kind,  since  its  second  term  is  not  an  object  of  which 
we  can  have  perception  and  experience,  that  is  to  say,  an  en- 
tire and  determined  fact,  but  a  portion  of  a  fact,  a  fragment  for- 
cibly and  artificially  severed  from  the  natural  whole  to  which  it 
belongs,  and  without  which  it  cannot  subsist. 

II.  Can  we  have  experience,  perception,  or  sensible  rep- 
resentation of  this  detached  and  isolated  fragment  ?  Assur- 
edly not ;  for  that  would  be  a  contradiction. — When  I  have  seen 
on  the  slate  triangles,  quadrilaterals,  pentagons,  hexagons,  etc. ; 
and,  in  contrast,  beside  them,  circles  and  ellipses,  and  call  the 
first  polygons,  I  have  not  mentally  a  sensible  representation  of 
a  pure  or  abstract  polygon  ;  for  the  pure  polygon  is  a  figure  with 
several  sides,  but  whose  sides  do  not  make  up  any  particular 
number ;  hence  all  experience  and  sensible  representation  are 
excluded ;  for  since  the  sides  are  many,  they  make  such  a  num- 
ber as  three,  four,  five,  six,  etc.  In  saying  many,  we  mean  a 
determined  fixed  number.  To  tell  one  to  see  or  imagine  many 
sides,  and  at  the  same  time  not  to  see  or  imagine  three,  four,  or 
any  definite  number  of  sides,  is,  in  one  breath,  to  order  and  forbid 
the  same  operation. — Similarly,  when  having  seen  in  the  country 
thirty  different  trees,  oaks,  lime  trees,  beach,  and  poplars  I  use 
the  word  tree,  I  do  not  find  in  my  mind  a  colored  figure  rep- 
resentative of  a  tree  in  general ;  for  a  tree  in  general  has  height, 
trunk,  leaves,  etc.,  without  having  any  particular  height,  trunk, 
or  leaves ;  and  it  is  impossible  to  represent  to  one's  self  size 
and  form,  unless  the  size  and  form  are  of  some  kind  or  oth- 
er— that  is  to  say,  individual  and  precise.  In  fact,  at  the 
word  tree,  especially  if  read  slowly  and  attentively,  there  rises 
in  me  a  vague  image — so  vague  that  I  cannot  for  the  moment 
say  whether  it  is  a  fir  or  an  apple  tree.  And  so  in  hearing  the 
word  polygon,  I  trace  in  my  mind,  but  very  indistinctly,  lines 
cutting  each  other,  and  tending  to  enclose  a  space,  without 
knowing  whether  the  figure  in  process  of  construction  will  turn 


CHAP.  II.]  SIMPLE   SUBSTITUTION.  g 

out  quadrilateral  or  a  pentagon.  But  this  uncertain  image  is 
not  the  abstract  tree,  nor  the  abstract  polygon ;  the  softness 
of  its  outline  does  not  hinder  its  having  a  particular  outline  ; 
it  is  shifting  and  obscure,  and  the  object  denoted  by  the  name  is 
neither  shifting  nor  obscure  ;  it  is  a  very  precise  extract,  and 
can  often  be  defined  exactly.  We  can  express  with  rigorous 
exactness  what  constitutes  a  triangle,  and,  almost  as  exactly, 
what  constitutes  an  animal.  The  triangle  is  a  figure  enclosed  by 
three  lines,  which  cut  each  other  in  pairs,  and  not  that  undecided 
image,  on  a  dusky  or  whitish  ground,  with  angles  more  or  less 
acute,  which  shifts  continually,  becoming  at  will  scalene,  or 
isosceles,  or  right  angled.  The  animal  is  an  organized  body 
which  is  nourished,  reproduces  its  species,  feels,  and  moves,  and 
not  that  formless  and  varying  thing,  changing  from  vertebrate 
to  articulate  or  to  mollusc,  and  only  emerging  from  its  indis- 
tinctness when  it  takes  the  color,  size,  and  structure  of  an  in- 
dividual. 

Thus  we  find  a  wide  gulf  between  the  vague  and  shifting 
image  which  the  name  suggests,  and  the  precise  and  fixed  ex- 
tract which  the  name  denotes. — The  reader  may  convince 
himself  of  this  by  considering  the  word  myriagon  and  its  mean- 
ing. A  myriagon  is  a  polygon  with  ten  thousand  sides.  It  is 
impossible  to  imagine  such  a  thing  even  when  definite  and 
special,  much  less  when  general  and  abstract.  However  lucid 
and  comprehensive  may  be  the  mind's  view,  after  five  or  six, 
twenty  or  thirty  lines  drawn  out  consecutively  with  great  dif- 
ficulty, the  image  becomes  confused  and  indistinct ;  and  yet  my 
conception  of  a  myriagon  has  nothing  confused  or  indistinct 
about  it.  What  I  conceive,  is  not  a  myriagon  like  this,  in- 
complete and  tumbling  to  pieces,  but  a  complete  myriagon  all 
whose  parts  co-exist  simultaneously ;  I  can  hardly  imagine  the 
first,  but  can  readily  conceive  the  second.  What  I  conceive 
then,  differs  from  what  I  imagine  ;  and  my  conception  is  not  the 
same  thing  as  the  shifting  figure  which  accompanies  it.  But,  on 
the  other  hand,  this  conception  exists  ;  there  is  something  in  me 
representing  the  myriagon,  and  corresponding  to  it  exactly. 
In  what  then  does  this  internal  representative — this  exact  cor- 
respondent— consist  ?  and  what  passes  within  me  when  I  hear 
a  general  name,  and,  by  means  of  it,  think  of  a  quality  common 


IO  OF  SIGNS.  [BOOK  I. 

to  many  individuals — of  a  general  thing — in  short,  of  an  abstract 
character  ? 

III.  To  answer  this,  let  us  consider  in  order  several  cases 
in  which,  when  we  have  gone  through  a  series  of  similar  objects, 
we  have  mentally  extracted  from  them  a  quality,  or  general 
character,  which  we  denote  by  an  abstract  name.     The  reader 
has  no  doubt  visited  galleries  of  pictures  arranged  in  schools ; 
if  we  walk  for  a  couple  of  hours  among  the  works  of  Titian, 
Tintoret,  Giorgione,  and  Veronese,  and  on  leaving  seat  our- 
selves on  a  bench,  and  close  our  eyes,  we  experience  reminis- 
cences of  what  we  have  seen ;  we  see  again  inwardly  such  and 
such  a  fair  or  rosy  half-bending  figure,  some  grand  old  man  ma- 
jestically draped  in  silken  robes,  strings  of  pearls  on  naked  arms, 
chestnut  hair  curling  over  a  snowy  neck,  colonnades  of  veined 
marble  rising  against  a  blue  sky,  here  and  there  the  sprightly 
figure  of  a  little  girl,  the  smile  of  a  goddess,  the  ample  propor- 
tions of  a  smooth  shoulder,  the  blaze  of  red  hangings  against  a 
green  background ;  in  short,  a  hundred  partial  and  disorderly 
revivals  of  what  we  have  just  seen.     If,  at  this  moment,  we 
seek  for  the  dominant  character  ruling  in  this  various  world, 
we  find  nothing ;  we  feel  indeed  that  it  is  beautiful,  but  do  not 
yerMistinguish  in  what  the  beauty  lies;  we  are  acted  on  by 
twenty  different  tendencies  which  rise  and  as  quickly  fade ;  we 
attempt  such  expressions  as  voluptuous,  rich,  facile,  luxuriant ; 
they  are  not  suitable,  or  but  partially  so.     We  then  begin  again 
by  dividing  our  inquiries,  we  pass  by  turns  in  review  landscapes, 
architecture,  dress,  types,  expressions,  attitudes,  coloring;  we 
find  for  each  of  these  fragments  some  principal  and  striking 
trait,  we  attempt  to  note  them  in  passing  by  a  familiar  or  ex- 
aggerated word,  then,  collecting  all  these  summaries  we  try  to 
summarize   them  further  in  some  abbreviative  phrase  which 
may  serve  as  a  focus  for  all  these  dispersed  rays.     We  approach 
our  object,  and  at  last  a  definitive,  or  nearly  definitive,  tendency 
is  disengaged.     It  appears,  in  words,  by  such  expressions  as  ex- 
pansiveness,  happiness,  noble  pleasure  ;  while  our  inner  sight 
has  at  the  same  moment  seized  on  some  corresponding  image, 
an  opening  flower,  a  smiling  face,  a  bending  unconstrained  form, 
the  rich  and  full  harmony  of  sweet-toned  instruments,  the  breath 
of  perfumed  air  in  the  country ;  here  are  expressive  compari- 


CHAP.  II.]  SIMPLE    SUBSTITUTION.  !  x 

sons  and  metaphors,  that  is  to  say,  sensible  representations, 
special  recollections,  revived  sensations,  all  analogous  in  tone 
and  character  to  what  we  have  just  experienced.  They  are 
effects  and  expressions  of  the  final  tendency  which  has  been 
formed. — In  the  case  of  an  artist,  the  formation,  disengagement, 
and  effects  of  the  tendency  are  plainer  still.  The  whole  body 
speaks ;  often,  if  at  a  loss  for  a  word,  a  gesture  expresses  the 
meaning ;  a  grimace,  a  start,  an  imitative  noise,  becomes  a  sign 
in  place  of  a  name ;  to  represent  an  avenue  of  old  oaks,  the 
stature  becomes  erect,  the  feet  are  planted  firmly  on  the  ground, 
the  arms  extend  stiffly,  or  form  sharp  angles  at  the  elbows ;  to 
represent  a  cluster  of  honeysuckle  or  ivy,  the  stretched-out 
fingers  trace  arabesques  in  the  air,  while  the  muscles  of  the  face 
assume  changing  folds. — This  mimicry  is  natural  language,  and 
with  some  habit  of  internal  observation  you  guess  the  corre- 
sponding mental  state.  In  fact,  the  experiences  we  undergo, 
and  their  images  which  recur  to  us,  are  not  pure  knowledge ; 
they  affect  us  while  they  teach  us ;  they  are  at  once  a  disturb- 
ance and  a  light.  Each  one  of  them  is  accompanied  by  one  or 
many  slight  shocks,  and  each  of  them  has  for  effect  one  or  more 
slight  tendencies.  Beneath  images  and  experiences,  vegetation 
that  thrives  in  the  light,  there  is  an  obscure  world  of  impulsions, 
repugnances,  startling  shocks,  sketchy,  disorderly,  discordant 
solicitations,  which  we  can  barely  distinguish,  but  which  are 
nevertheless  the  inexhaustible  and  ever-springing  source  of  our 
actions.  These  are  the  countless  little  emotions  which,  at  the 
close  of  our  prolonged  examination,  sum  themselves  up  in  an 
impression  of  a  whole,  and  consequently,  in  a  final  and  definite 
tendency,  and  this  tendency  results  in  an  expression.  What- 
ever this  expression  may  be — the  imitative  gesture  of  the  artist, 
the  metaphorical  half-sight  of  the  poet,  the  expressive  panto- 
mime of  the  savage,  the  animated  tones  of  the  impassioned  man, 
the  dry  tone  and  abstract  language  of  the  calm  reasoner — the 
mental  operation  is  always  the  same;  and  if  we  inquire  into 
wrhat  passes  in  us  when,  from  several  perceptions,  we  disen- 
gage a  general  idea,  we  find — and  find  only — the  formation, 
completion,  and  preponderance  of  a  tendency  uiJtich  urges  an 
expression,  and,  among  other  expressions,  a  name. 

To  revert  to  our  first  example. — I  observe  in  turn  pines, 


12  OF  SIGNS.  [BOOK  I. 

ash,  chestnuts,  beech,  oak,  a  whole  forest ;  I  remark  the  spring- 
ing trunk  and  spreading  branches  which  form  the  two  distinct- 
ive characters  of  a  tree  ;  I  form  a  general  conception  of  a 
tree  and  use  the  word  tree.  This  simply  means  that  a  certain 
tendency  in  my  mind  corresponding  to  these  two  characters — 
and  to  these  two  characters  only — has  at  last  become  distinct 
and  predominant.  On  fifty  consecutive  occasions,  and  with- 
out a  single  contradictory  instance,  it  has  in  turn  been  aroused 
at  the  sight  of  fifty  trees  ;  and  it  only  has  been  aroused  on  each 
one  of  these  fifty  occasions.  All  other  tendencies  correspond- 
ing to  the  peculiarities  of  the  different  trees,  are  effaced  and 
annulled  by  mutual  contradiction  ;  it  alone  survives,  and  results, 
as  do  all  tendencies,  in  an  expression.  Mentally,  this  result  is 
an  image,  more  or  less  vague — that  of  a  slender,  then  spread- 
ing stem ;  outwardly,  it  becomes  the  attitude  and  imitative 
gesture  of  the  body  ;  in  primitive  language,  among  infant  races, 
at  the  origin  of  speech,  it  is  a  poetical  and  figurative  imitation 
of  another  kind,  of  which  we  find  fragments  here  and  there  ; 
now-a-days,  it  has  become  a  simple  word,  which  we  learn  purely 
by  way  of  notation,  the  dry  remains  of  the  little  symbolical 
drama  and  living  mimicry  by  which  the  first  inventors,  true 
artists,  translated  their  impressions. 

IV.  The  reader  now  sees  how  it  is  we  conceive  a  general 
quality ;  when  we  have  seen  a  series  of  objects  possessing  a 
common  quality,  we  experience  a  certain  tendency,  a  tendency 
which  corresponds  to  the  common  quality,  and  to  it  alone.  It 
is  this  tendency  which  calls  up  the  name ;  and  when  it  arises 
the  name  only  is  imagined  or  pronounced.  We  do  not  perceive 
qualities  or  the  general  characters  of  things  ;  we  only  experience 
in  their  presence  such  and  such  a  distinct  tendency,  which,  in 
spontaneous  language,  results  in  a  certain  mimicry,  and,  in  our 
artificial  language,  in  a  certain  name.  We  have,  strictly  speak- 
ing, no  general  ideas  ;  we  have  tendencies  to  name  and  names. 
— But  a  tendency  is  nothing  distinct  in  itself;  it  is  the  com- 
mencement, the  rudiment,  the  sketch,  the  approximation, 
whether  easy  or  difficult,  to  some  thing,  image,  or  name,  or  other 
determinate  act,  which  is  its  full  development  and  accomplish- 
ment ;  it  is  the  elementary  form  of  the  act  which  is  its  final 
state. — As  to  positive  and  definite  acts,  when  we  conceive  or 


CHAP.  II.]  SIMPLE   SUBSTITUTION.  l^ 

know  abstract  qualities,  all  that  passes  in  us  are  names,  some 
in  process  of  being  expressed  or  mentally  imagined ;  others  al- 
ready expressed  and  imagined.  What  therefore  we  call  a  gen- 
eral idea,  a  comprehensive  view,  is  only  a  name ;  no't  the  sim- 
ple sound  that  vibrates  in  the  air  and  strikes  our  ear,  or  the 
collection  of  letters  which  blacken  the  paper  and  attract  the 
eye,  not  even  these  letters  perceived  mentally,  or  this  sound 
pronounced  mentally,  but  this  sound  or  these  letters  endued, 
when  we  experience  or  imagine  them,  with  a  double  property, 
that  of  arousing  in  us  images  of  individuals  belonging  to  a  cer- 
tain class,  and  of  these  individuals  only ;  and  the  property  of 
reviving  when,  and  only  when,  an  individual  of  this  same  class 
is  present  to  our  memory  or  experience. — The  only  difference 
between  the  word  tree,  which  has  a  meaning,  and  the  word  eter, 
which  has  none,  is  that  on  hearing  the  second  we  do  not  imag- 
ine any  object  or  series  of  objects  belonging  to  a  distinct  class, 
and  there  is  no  object  or  series  of  objects  belonging  to  a  distinct 
class  which  suggest  to  us  such  a  word,  whilst  on  hearing  the 
first  word  we  involuntarily  picture  to  ourselves  an  oak,  a  pop- 
lar, a  pear  tree,  or  some  other  tree,  and  on  seeing  a  tree,  of 
whatever  kind,  we  involuntarily  pronounce  the  word  tree.  In- 
stead of  eter  put  the  word  arbre  ;  to  any  one  unacquainted  with 
French,  the  two  words  are  of  equal  value,  and  result  in  the  same 
want  of  effect ;  to  a  Frenchman  the  word  arbre  has  precisely 
the  properties  which  we  have  just  found  in  the  word  tree. — A 
name,  then,  which  we  understand  is  a  name  connected  with  all 
the  individuals  which  we  can  perceive  or  imagine  belonging  to 
a  certain  class  and  only  with  the  individuals  of  this  class.  In 
this  way  it  corresponds  to  the  common  and  distinctive  quality 
which  constitutes  the  class  and  separates  it  from  other  things, 
and  corresponds  to  this  quality  only ;  wherever  the  quality  is, 
there  is  the  name ;  whenever  this  quality  is  absent  there  is  no 
name  ;  it  is  aroused  by  it,  and  by  it  only. — Thus  it  becomes  its 
mental  representative,  and  the  substitute  of  an  experience  to 
which  we  cannot  attain.  It  stands  in  place  of  this  experience, 
it  fulfils  its  office,  and  is  equivalent  to  it. 

Admirable  and  spontaneous  artifice  of  our  nature  :  we  can 
neither  perceive  general  qualities  nor  maintain  them  separate 
in  our  minds ;  and  yet,  they  are  the  precious  veins  which  con- 


!4  OF  SIGNS.  [BOOK  I. 

stitute  the  essence  and  are  the  foundation  of  the  classification 
of  things,  and,  to  enable  us. to  emerge  from  gross  animal  expe- 
rience, to  seize  the  order  and  internal  structure  of  the  world, 
we  must  draw  them  from  their  ore  and  conceive  them  apart. — 
We  make  a  circuit,  we  associate  with  each  abstract  and  gener- 
al quality  a  little  special  complex  fact,  a  sound,  a  figure  easy 
to  imagine  and  reproduce  ;  we  make  the  association  so  close 
and  precise,  that  henceforward,  the  quality  cannot  appear  or  be 
missing  in  things  without  the  appearance  or  absence  of  the  name 
in  our  minds,  and  reciprocally.  The  couple  so  formed  resem- 
bles those  physical  and  chemical  instruments,  which,  by  a  tri- 
fling sensible  change,  the  displacement  of  a  needle,  the  altera- 
tion of  a  color,  bring  within  the  range  of  our  senses,  decompo- 
sitions of  substances,  or  variations  of  currents,  to  which  our 
senses  cannot  otherwise  attain.  The  sudden  reddening  of  a 
stained  paper  or  the  greater  or  less  twist  of  a  suspended  needle 
are  connected  with  an  inner  change  or  a  certain  degree  of  hid- 
den action,  and  we  observe  the  second  things  to  which  we  can- 
not directly  attain,  in  the  first  to  which  we  do  attain. — And 
similarly,  when  we  are  dealing  with  a  general  quality  of  which 
we  can  have  neither  experience  nor  sensible  representation,  we 
substitute,  and  substitute  legitimately,  a  name  for  the  impossible 
representation.  It  has  the  same  affinities  and  repugnances  as 
the  representation,  the  same  hindrances  to  and  conditions  of  ex- 
istence, the  same  extent  and  limits  of  presence ;  affinities  and 
repugnances,  hindrances  and  conditions  of  being,  extent  and 
limits  of  presence,  all  we  meet  in  the  one  we  meet,  indirectly, 
in  the  other. — Owing  to  this  correspondence,  the  general  char- 
acters of  things  are  brought  within  range  of  our  experience  ;  for 
the  names  expressing  them  are,  themselves,  either  small  expe- 
riences of  sight,  the  ear,  the  vocal  muscles,  or  internal  images, 
that  is  to  say,  revivals  more  or  less  clear,  of  these  experiences. 
An  extraordinary  difficulty  has  been  surmounted  ;  with  beings 
whose  life  is  but  one  varied  and  continuous  experience,  special 
and  complex  impressions  can  alone  be  found  ;  out  of  these  spe- 
cial and  complex  impressions  nature  has  manufactured  the  equiv- 
alents of  others,  which  are  neither  special  nor  complex,  and 
which,  as  they  cannot  be  so,  would  seem  as  if  they  must  escape 
forever  by  necessity  and  nature  from  beings  constituted  as  we  are. 


CHAP.  II.]  SIMPLE   SUBSTITUTION.  :  e 

V.  The  formation  of  these  general  names  may  be  narrowly 
watched  ;  with  little  children,  we  take  them  in  the  act.  We 
name  to  them  such  and  such  a  particular  determined  object, 
and,  with  an  instinct  of  imitation  common  to  them  with  mon- 
keys and  parrots,  they  repeat  the  name  they  have  just  heard. 
—Up  to  this  point  they  are  but  as  monkeys  and  parrots ;  but 
here  there  appears  a  delicacy  of  impression  which  is  special  to 
man.  We  pronounce  the  word  papa  before  a  child  in  its  cra- 
dle, at  the  same  time  pointing  out  his  father.  After  a  little, 
he  in  his  turn  lisps  the  word,  and  we  imagine  that  he  under- 
stands it  in  the  same  sense  that  we  do,  or  that  his  father's  pres- 
ence only  will  recall  the  word.  Not  at  all.  When  another  per- 
son— that  is,  one  similar  in  appearance,  with  a  long  coat,  a 
beard,  and  loud  voice — enters  the  room,  he  calls  him  also 
papa.  The  name  was  an  individual  one  ;  he  has  made  it  gen- 
eral. In  our  case,  it  is  applicable  to  one  person  only ;  in  his, 
to  a  class.  In  other  words,  a  certain  tendency,  corresponding 
to  what  there  is  in  common  to  all  persons  in  long  coats,  with 
beards  and  loud  voices,  is  aroused  in  him  in  consequence  of  the 
experiences  by  which  he  has  perceived  them.  This  tendency  is 
not  what  you  were  attempting  to  excite ;  it  springs  up  spon- 
taneously. In  it  we  have  the  faculty  of  language.  It  is 
wholly  founded  on  the  consecutive  tendencies  which  survive 
the  experience  of  similar  individuals,  and  corresponds  precise- 
ly to  what  they  have  in  common. 

We  see  these  tendencies  continually  at  work  in  children, 
and  leading  to  results  differing  from  ordinary  language ;  so  that 
we  are  obliged  to  correct  their  spontaneous  and  too  hasty  at- 
tempts.— A  little  girl,  two  years  and  a  half  old,  had  a  blessed 
medal  hung  at  her  neck.  She  had  been  told,  "  Ccst  le  bon 
Dieu"  and  she  repeated,  "  Ccst  le  bo  Du."  One  day,  on  her 
uncle's  knee,  she  took  his  eyeglass,  and  said,  "  Ccst  le  bo  Du 
de  mon  onclc"  It  is  plain  that  she  had  involuntarily  and  nat- 
urally constructed  a  class  of  objects  for  which  we  have  no 
name ;  that  of  small  round  objects,  with  a  handle,  through 
which  a  hole  is  pierced,  and  hung  around  the  neck  by  a  ribbon ; 
that  a  distinct  tendency,  corresponding  to  these  four  general 
characters,  and  which  we  do  not  experience,  was  formed  and 
acting  in  her. — A  year  afterwards,  the  same  child,  who  was 


1 6  OF  SIGNS.  [BOOK  I. 

being  asked  the  names  of  different  parts  of  the  face,  said  after 
a  little  hesitation,  on  touching  her  eyelids,  "  These  are  the  eye- 
curtains." — A  little  boy,  a  year  old,  had  travelled  a  good  deal 
by  railway.  The  engine,  with  its  hissing  sound  and  smoke,  and 
the  great  noise  of  the  train,  struck  his  attention,  and  the  first 
word  he  learned  to  pronounce  wasfafcr  (chemin  de  fer).  Hence- 
forward, a  steamboat,  a  coffee-pot  with  spirit-lamp — every  thing 
that  hissed  or  smoked,  or  made  a  noise,  was  ^fafer.  Anoth- 
er instrument  to  which  children  have  a  great  objection  (excuse 
the  detail  and  the  word — I  mean  a  clysoponipe]  had,  naturally 
enough,  made  a  strong  impression  on  him.  He  had  termed 
it,  from  its  noise,  a  zizi.  Till  he  was  two  years  and  a  half  old, 
all  long,  hollow,  slender  objects — a  scissors-sheath,  a  cigar-tube, 
a  trumpet,  were  for  him  zizi,  and  he  treated  them  all  with  dis- 
trust. These  two  reigning  ideas,  the  zizi  and  the  fafer,  were 
two  cardinal  points  of  his  intelligence,  and  from  them  he  set 
out  to  comprehend  and  name  other  things. 

In  this  respect  the  language  of  children  is  as  instructive  to 
a  psychologist  as  the  embryonic  states  of  organized  bodies  are 
to  the  naturalist.  Their  language,  unlike  ours,  is  living,  and 
incessantly  on  the  change ;  not  only  are  words  defaced  or  in- 
vented, but,  more  than  this,  the  sense  of  words  is  not  the  same 
as  in  our  language.  A  child  who  pronounces  a  name  for  the  first 
time  never  takes  it  in  the  precise  sense  which  we  give  it.  This 
sense  is  more  or  less  extensive  to  him  than  to  us ;  it  is  propor- 
tioned to  his  experience  at  the  time ;  is  enlarged  or  reduced 
daily  by  his  new  experience,  and  brought  very  slowly  down  to 
the  precise  dimensions  which  it  has  for  us.* — A  little  girl,  of 
eighteen  months  old,  had  been  heartily  amused  by  her  mother, 
or  nurse,  hiding  in  play  behind  the  door  or  chair,  and  saying, 
"  Coucou"  Again,  when  her  dinner  was  too  hot ;  when  she 
went  too  near  the  fire  ;  when  she  put  out  her  hand  to  the  can- 


*  An  analogous  difference  appears  in  comparing  the  synonyms  in  two  languages  : 
clergyman  and  ecclesiastiqtie,  God  and  Dieu,  llebe  and  amour,  brio  and  brillant,  girl 
and  jeun£  fille,  do  not  respectively  mean  the  same  things,  though  we  translate  one 
by  the  other.  The  two  words  of  each  couple  represent  two  different  objects,  and 
are  differently  understood  by  the  two  peoples.  Their  senses  is  the  same  in  the  rough  ; 
the  details  of  their  meanings  are  different  and  untranslatable  in  the  absence  of  sim- 
ilar objects  and  emotions  in  the  two  cases. 


CHAP.  II.]  SIMPLE    SUBSTITUTION.  ij 

die ;  when  they  put  on  her  hat  in  the  garden,  to  keep  off  the 
hot  sun,  she  was  told  "  Ca  bride"  Here  were  two  remarkable 
words  which,  to  her,  represented  things  of  supreme  impor- 
tance ;  her  most  painful  sensation  and  her  most  pleasurable 
one.  One  day,  seeing  from  a  terrace  the  sun  disappearing  be- 
hind a  hill,  she  said,  "A  bule  coucou."  Here  we  have  a  com- 
plete judgment,  not  only  expressed  by  words  which  we  do  not 
employ,  but  also  corresponding  to  ideas,  consequently  to  class- 
es of  objects,  to  general  characters,  to  distinct  tendencies,  which 
in  our  cases  have  disappeared.  The  hot  soup,  the  fire  on  the 
hearth,  the  flame  of  the  candle,  the  noonday  heat  in  the  gar- 
den, and  last  of  all,  the  sun,  make  up  one  of  these  classes.  The 
figure  of  the  nurse  or  mother  disappearing  behind  a  piece  of 
furniture,  the  sun  disappearing  behind  a  hill,  form  the  other 
class.  Both  are  limited  to  this ;  the  tendency  consecutive  to 
the  first  resulted  in  the  words  a  bule ;  the  tendency  consecu- 
tive to  the  second  in  the  word  coucou. — Such  a  state  of  mind 
differ.5  greatly  from  ours ;  but,  nevertheless,  it  consists  of  ten- 
dencies analogous  to  ours,  aroused  in  the  same  way  as  ours, 
corresponding  to  general  characters  as  with  us,  but  to  characters 
less  general,  in  short,  resulting  in  names  similar  in  sound  and 
different  in  sense. 

In  proportion  as  the  experience  of  children  approaches 
more  nearly  to  our  own,  their  tendencies  to  name  coincide 
more  exactly  with  ours  ;  they  become  organized  by  degrees 
like  embryos.  As  in  the  foetus,  we  see,  in  turn,  the  dispropor- 
tionate head  reduced  to  its  proper  proportions,  the  sutures  of 
the  skull  harden,  the  cartilage  turn  into  bone,  the  rudimenta- 
ry vessels  close  and  ramify,  the  communication  between  child 
and  mother  become  obstructed  ;  so  do  we  see,  in  the  language 
of  children,  the  two  or  three  dominant  words  lose  their  abso- 
lute preponderance,  the  general  words  limit  their  too  extensive 
meaning,  gain  precision  for  their  vagueness  of  sense,  acquire 
connections,  attachments  and  sutures  with  each  other,  become 
complete  by  the  incorporation  of  other  tendencies,  become  ar- 
ranged under  these  into  names  of  smaller  classes,  form  a  sys- 
tem corresponding  to  the  order  of  beings,  and  at  last  act  by 
themselves  alone,  and  of  themselves,  without  the  aid  of  assisting 
namegivers. — A  child  has  watched  its  mother  put  on  her  white 


1 8  OF  SIGNS.  [BOOK  I. 

dress  for  a  ball ;  he  has  remembered  the  word,  and  in  future, 
when  he  meets  a  lady  in  evening  dress,  whether  she  has  on  red 
or  blue,  he  will  say  in  his  singing,  curious,  happy  voice,  "  You 
have  put  on  your  white  dress''  White  is  too  large  a  word  ;  he 
will  have  for  the  future  to  reduce  its  application  to  a  single  col- 
or.— The  same  child  hears  his  mother  say  to  him,  "  You  swine 

*  o 

your  head  too  much  ;  it  will  strike  the  table."  He  says,  in  a 
curious  and  surprised  way,  "Your  head  will  strike  the  table?" 
Your  again  has  received  too  large  a  sense  ;  he  must  be  taught 
to  reduce  it  to  mean  the  head  only  of  the  person  he  is  speak- 
ing to. — The  process  of  checking  goes  on  ;  new  experience 
will  complete  the  tendency  which  produced  the  word  white, 
and  once  accomplished,  it  will  correspond  not  only  to  the  pres- 
ence of  bright  fresh  color,  but,  more  than  this,  to  the  presence 
of  a  particular  color.  Similarly,  and  by  another  series  of  expe- 
riences, the  tendency  which  produced  the  word  your  when  given 
definite  precision,  will  correspond  not  only  to  possession,  but 
also  to  this  supplementary  circumstance,  that  the  thing,  pos- 
sessed belongs  to  the  person  spoken  to.  Such  is  the  history 
of  language  :  we  experience  spontaneously,  after  having  come 
in  contact  with  a  series  of  similar  objects,  a  tendency  which 
corresponds  to  what  there  is  in  common  to  these  objects ;  that 
is  to  say,  to  some  general  character,  to  some  abstract  quality, 
to  an  extract  from  the  objects,  and  this  tendency  results  in  a 
gesture,  in  some  mimicry,  in  some  distinct  sign,  which  in  ma- 
turity becomes  a  name. 

Herein  consists  the  superiority  of  the  human  intelligence. 
Very  general  characters  arouse  in  it  distinct  tendencies,  in 
other  words,  very  slight  resemblances  between  different  objects 
are  sufficient  to  exite  in  us  a  name  or  spesial  designation ; 
a  child  succeeds  here  without  effort,  and  the  genius  of  well- 
endowed  races,  as  that  of  great  men,  and  notably  of  inventors, 
consists,  in  observing  resemblances  more  or  less  delicate  and 
novel ;  that  is,  in  feeling  arise  in  them,  at  the  sight  of  objects, 
certain  slight  and  delicate  tendencies,  and  consequently,  distinct 
names,  which  correspond  to  shades  imperceptible  to  ordinary 
minds,  to  the  very  slight  characters  hidden  beneath  a  heap  of 
the  coarse,  striking  circumstances,  alone  capable,  when  the  mind 
is  ordinary,  of  leaving  an  impression  upon  it,  and  having  a 


CHAP.  II.]  SIMPLE   SUBSTITUTION.  rg 

response  in  it. — This  aptitude  once  established,  the  rest  follows. 
By  the  accumulation  and  contrariety  of  daily  experiences,  ten- 
dencies and  names  multiply,  are  circumscribed,  and  become 
subordinated,  like  the  general  qualities  they  represent;  and 
the  hierarchy  of  things  is  translated  and  repeated  within  us  by 
the  hierarchy  of  tendencies  and  names. 

VI.  On  the  other  hand,  if  we  may  use  the  expression,  names 
fill  out.  In  proportion  as  our  experiences  become  more  numer- 
ous, we  remark  and  consequently  name  a  greater  number  of 
general  characters  in  the  same  object.  Its  name,  which  at  first 
denoted  the  single  character  which  struck  us  at  first  sight,  now 
denotes  several  others.  It  now  corresponds,  not  to  an  abstract 
quality,  but  to  a  group  of  abstract  qualities  ;  it  was  only  general, 
it  becomes  collective. 

Take  any  animal,  a  cat,  for  instance.  As  all  cats  have  points 
of  strong  resemblance,  and  differ  a  good  deal  from  our  other 
animals,  we  have  no  difficulty  in  learning  their  common  name, 
and  observing  their  common  characteristics.  In  other  words, 
this  name  corresponds  to  a  certain  distinct  form,  at  rest  or 
moving,  sleeping  in  a  stable,  or  creeping  cautiously  along  a  roof. 
This  is  the  common  popular  sense,  and  the  tendency  which  re- 
sults in  the  name  corresponds  to  little  more  than  this. — But  a 
naturalist  takes  me,  and  opening  a  cat,  shows  me  the  pouch  we  call 
the  stomach,  the  little  vessels  we  call  veins  and  arteries,  with 
their  infinite  ramifications ;  the  collection  of  smooth  tubes 
which  are  the  intestines,  and  the  .bars,  arches,  frames,  cavities, 
and  hinges,  which,  with  their  connections,  make  up  the  skeleton. 
—I  might  remain  for  six  months  continually  seeing  new  things. 
If  I  were  to  work  with  a  microscope,  my  life  would  not  be  long 
enough,  and,  speaking  accurately,  no  life  or  series  of  lives  would 
suffice ;  beyond  the  observed  properties,  there  will  always  re- 
main others  unobserved,  tl\e  unlimited  matter  of  an  unlimited 
science.  Henceforward  the  name  corresponds  for  me,  not 
merely  to  the  experience  of  a  certain  external  form,  but  also 
to  that  of  a  certain  internal  structure,  that  is,  to  an  enormous 
number  of  various  phenomena  which  I  have  experienced,  and 
to  an  indefinite  number  which  I  might  experience.  If  I  have 
paid  sufficient  attention  to  the  internal  structure,  I  shall  pro- 
nounce the  word  cat  as  confidently  when  I  see  the  blanched 


2O  OF  SIGNS.  [BOOK  I. 

skeleton,  as  at  the  sight  of  the  living  furry  body.  The  second 
experience  now  results  in  the  same  name  as  the  first.  Two 
distinct  tendencies  coincide  therefore  in  the  same  effect.  The 
name  has  become  the  equivalent  of  the  characters  common  to 
the  different  skeletons  of  the  kind,  as  of  the  characters  common 
to  the  different  living  animals  of  the  kind ;  its  presence,  which 
once  aroused  images  only  of  certain  velvety,  living,  bounding 
forms,  now  arouses  also  images  of  certain  bony  lifeless  frame- 
works.— It  may  arouse  many  other  images,  those  of  all  the 
mechanical,  physical,  chemical,  anatomical,  vital,  moral  peculi- 
arities which  naturalists  and  moralists  can  discover  in  the  race 
of  cats  ;  it  assembles  them  all  in  itself,  together  with  the  names 
we  denote  them  by;  it  is  the  substitute  of  the  whole  band. 
On  hearing  the  name  cat,  we  can  substitute  for  it  a  definition 
or  a  description — that  is  to  say,  replace  it  either  by  the  two 
principal  names  which  determine  its  rank  in  the  classification 
of  animals,  or  by  the  names  of  all  the  characters  which  our  ex- 
periences have  discovered  in  it,  and  consequently,  recall  more 
or  less  vividly  to  our  minds,  the  likenesses  of  such  experiences. 
Henceforth,  the  couple  whose  first  term  is  the  name,  comprises 
as  second  term,  an  immense  list  of  other  words,  and  conse- 
quently, as  great  a  series  of  distinct  tendencies,  which  corre- 
spond to  general  characters  equally  distinct,  and  leave  room  be- 
side them  for  an  infinite  number  of  new  tendencies  which  ex- 
perience may  excite. — Such  is  the  power  of  the  substitution 
established  by  couples.  Two.  terms  being  the  equivalents  of 
one  another,  the  first,  which  is  so  simple,  so  manageable,  so 
easy  to  recall,  is  capable  of  replacing  the  second,  even  when  the 
second  is  an  immense  army,  whose  lists  always  open,  await  and 
are  continually  receiving  new  soldiers. 

The  reader  sees  at  once  that  in  place  of  the  name  cat  we 
might  put  that  of  dog,  monkey,  crab,  or  of  any  animal  or  plant 
whatever  ;  or  again,  that  of  any  group,  animal  or  vegetable,  as 
extensive  or  as  narrow  as  we  please,  and,  in  general,  of  any  group 
moral  or  physical.  The  operation  would  be  similar ;  all  general 
names  acquire  extensions  of  meaning  in  the  same  way. — Ar- 
ranged in  relation  to  one  another,  each  with  its  retinue  of  ten- 
dencies, they  make  up  the  principal  furniture  of  a  thinking 
brain.  By  the  side  of  continual  experiences  and  reviving  im- 


CHAP.  II.]  SIMPLE   SUBSTITUTION.  21 

ages,  there  are  names  which  we  term  ideas  ;  all  of  them  mental 
representatives  of  abstract  characters  and  general  qualities,  each 
one  called  up' by  some  distinct  tendency,  all  incessantly  extend- 
ed by  new  tendencies,  gaining  precision  in  their  application,  and 
increased  in  their  contents  by  the  daily  progress  of  discovery  y 
which,  adding  to  their  meanings,  limits  their  application. 


22  OF  SIGNS.  [BOOK.  I. 


CHAPTER  III. 

OF   GENERAL  IDEAS  AND   REPEATED   SUBSTITUTIONS. 

I.  THERE  are  things  of  which  we  can  have  no  experience ; 
now,  since  experiences  are  what,  by  their  common  character, 
arouse  in  us  a  distinct  tendency  and  the  name  which  we  term 
an  idea,  it  seems  as  if  we  could  never  attain  to  ideas  of  such 
things.  We  have,  nevertheless,  very  clear  and  exact  ideas  of 
them.  The  operation,  which  consists  in  giving  names  to  things, 
becomes  complicated,  and  leads  us  by  a  circuit  to  unhoped-for 
successes.  The  same  instrument  is  at  work  as  before,  but  it 
works  by  a  series  of  substitutions,  instead  of  a  simple  sub- 
stitution. 

Consider  the  first  number  that  comes  to  hand :  36,  for  ex- 
ample. When  I  read  this  sign,  I  thoroughly  understand  its 
sense  ;  that  is,  I  clearly  imagine  what  it  replaces.  36  is  by  defini- 
tion ^plus  i.  In  other  words,  the  group  we  call  36  is  the  same 
as  that  which  we  call  35,  if  to  35  we  add  I.  36,  then,  is  a  col- 
.lective  term  which  replaces  two  others.  But  3 5,  by  definition,  is 
34 plus  I ;  34,  again,  is  33  phis  I ;  and  so  on.  36,  then,  in  final 
analysis,  is  an  abbreviatory  expression  which  replaces  thirty-six 
others.  Let  us  go  back  to  the  elements,  the  better  to  under- 
stand this  operation. 

Suppose  a  red  counter  at  one  corner  of  the  table,  and  a 
white  one  at  another.  I  may  neglect  all  their  respective  qual- 
ities, and  be  struck  solely  with  the  fact  that  a  part  of  my  im- 
pression is  repeated,  and  feel  that  what  I  have  just  experienced 
in  the  case  of  the  red  counter  is,  up  to  a  certain  point,  similar 
to  what  has  happened  in  the  case  of  the  white,  and  after  the 
two  several  experiences,  may  feel  a  distinct  consecutive  tenden- 
cy, corresponding  to  their  number,  that  is,  to  the  property  they 
have  of  being  two. — This,  like  all  other  tendencies,  results  in  a 
sign  ;  let  us  take  for  this  sign  the  ordinary  word,  two.  Here 
is  a  general  name ;  we  shall  be  inclined  to  pronounce  it,  as 


CHAP    III.]  REPEATED   SUBSTITUTIONS.  33 

in  the  case  of  the  counters,  after  each  repeated  experience. 
Similarly,  too,  when  we  read  it,  or  hear  it,  we  have  only  to  dwell 
on  it  to  call  up  inwardly,  as  with  the  word  cat  or  birch-tree,  an 
image  of  a  case  to  which  it  is  applicable  ;  we  think  of  a  counter 
beside  a  counter,  a  stone,  a  sound  followed  by  a  sound,  as  just  now 
we  imagined  a  tapering  face  with  white  or  gray  fur,  a  slender  white 
trunk  with  small  quivering  leaves. — The  same  is  the  case  with 
the  words,  three,  four ;  it  is  more  difficult  with  the  words,  five, 
six  ;  the  difficulty  increases  with  the  higher  numbers,  and  there 
is  always  a  figure,  larger  or  smaller,  at  which  the  mind  stops  ; 
we  cannot  perceive  or  represent  distinctly  to  ourselves  as  a 
whole,  more  than  a  certain  number  of  facts  or  objects  ;  generally 
five  or  six,  more  often  four. — To  remedy  this  inconvenience  we 
neglect  the  group  corresponding  to  the  word,  and  fix  our  whole 
attention  on  the  word  we  have  substituted  for  it ;  after  seeing 
four  objects  together  we  forget  them,  and  think  only  of  the  word 
four,  and  this  is  allowable,  since  when  later  on  we  return  to 
the  word  and  consider  it,  we  shall  see  the  objects  again  in  our 
minds  without  mistake  or  confusion.  Here  then  we  have  four 
operations  replaced  by  one  only. — When  a  new  object,  similar  to 
the  foregoing  ones,  is  met  with  after  we  have  pronounced  the 
word  four,  it  will  form,  with  the  word,  a  new  group,  and  will  excite 
in  us  a  tendency  analogous  to  that  which  made  us  use  the  word  two 
— a  tendency  similar  to  the  first  from  its  involving  an  addition, 
differing  from  the  first  from  its  being  an  addition,  not  of  one 
object  to.  another,  but  of  an  object  to  a  group  of  four  objects. 
This  new  tendency  results  in  a  new  name,  five.  Another,  excited 
by  this  previous  one,  will  result  in  the  word  six,  and  so  on. — 
We  see  that  in  this  scale  each  new  name  is  the  substitute  of  the 
preceding  one, — and  consequently  of  the  object  of  the  pre- 
ceding one — joined  to  unity. 

Here,  again,  an  insurmountable  difficulty  has  been  evaded. 
If  we  can  imagine  distinctly  as  a  whole  two,  three,  or  even  four 
objects,  we  cannot  do  so  with  respect  to  36  as  a  whole.  .  The 
abstract  and  general  property  of  being  two,  three,  or  four,  may 
arouse  in  us  a  tendency,  arid  consequently  a  corresponding 
name  ;  on  the  other  hand,  the  general  and  abstract  property 
of  being  36,  or  any  other  considerable  number,  cannot  do  this. 
— Before  an  obstacle  like  this  we  must  proceed  indirectly  ;  we 


24  .  OF  SIGNS.  [BOOK  I. 

bridge  over  the  ditch  too  wide  for  our  legs.  We  no  longer 
replace  at  once  by  a  word  the  general  and  abstract  character 
of  the  group  in  question  ;  for  experience  cannot  successfully 
attain  to  such  a  group.  Thirty-six  pawns  on  a  chess-board 
give  an  impression  only  of  a  mass  and  a  whole,  without  distinct 
numerical  knowledge  of  the  individuals. — We  proceed  more 
slowly ;  we  first  take  a  very  small  group,  proportioned  to  the 
limited  range  of  our  minds,  and  capable  of  arousing  in  us  a  ten- 
dency and  a  name.  We  next  join  this  name,  and  consequently 
the  object  of  the  name,  that  is,  the  little  group,  to  a  new  indi- 
vidual, and  this  arouses  in  us  another  tendency  and  another 
name  ;  and  thus  step  by  step  we  journey  on  to  the  final  name, 
and  this  once  obtained,  corresponds  to  the  abstract  character 
which  did  not  directly  arouse  a  name. 

In  this  respect  the  final  name  is  very  remarkable.     If  we 
look  for  its  sense  we  find  a  name  only,  that  of  the  lower  figure 
to  which  we  add  unity ;  the  same  thing  happens  with  this  lower 
figure,  and  so  on  ;  it  is  only  at  the  end  of  this  retracement  of  " 
our  steps,  when  we  have  descended  some  30,  50,  100,  1000,  or 
10,000  stories,  that  we  arrive  again  at  our  experience. — And 
yet  this  name  replaces  an  experience,  another  experience  which 
we  have  not  attained,  which  we  cannot  attain,  which  is  above 
man's  powers,  but  which  is  in  itself  possible,  and  which  a  more 
comprehensive  mind  might  attain  to :  36  denotes  the   quality 
common  to  all  groups  of  36  individuals  ;  a  quality  which,  as  pre- 
sented to  us,  does  not  excite  any  precise  tendency,  and  which 
a  mind  capable  of  representing  before  it  at  once  36  objects  or 
facts  in  a  distinct  state,  would  alone  experience.     By  this  arti- 
fice, we  attain  the  same  results  as  creatures  endowed  with  im- 
aginations and  memories  far  more  clear  and  vast  than  our  own. 
Here,  as  before,  all  has  been  effected  by  substitution.     After 
having  enabled  us  to  arrive  at  abstract  qualities,  she  affords  us 
the  means  of  counting  and  measuring  quantities.     Thanks  to 
substitutions,  we  were  enabled  to  conceive  the  abstract  qualities 
of  individuals.     Thanks  to  a  series  of  repeated  substitutions, 
we  are  able  to  name,  and  consequently  to  conceive,  certain  ab- 
stract properties  peculiar  to  groups — properties  which  the  natu- 
ral limitation  of  our  imagination  and  memory  seemed  to  hinder 
us  from*  ever  conceiving,  that  is  to  say,  from  naming. 


CHAP.  III.]  REPEATED   SUBSTITUTIONS.  25 

II.  The  efficiency  of  substitution  extends  far  beyond  this. 
— As  the  reader  knows,  geometrical  objects  do  not  exist  in  na- 
ture. We  do  not  meet,  and  probably  can  never  meet,  with 
perfect  circles,  cubes,  and  spheres.  Those  we  see  or  construct 
are  but  approximately  so. — Nevertheless,  we  conceive  them  as 
perfect ;  we  reason  about  figures  of  absolute  regularity.  We 
know,  with  complete  certainty,  what  is  the  obtuseness  of  each 
angle  in  a  regular  myriagon,  and  to  how  many  right  angles  the 
whole  of  its  angles  taken  together  amount.  Besides  this,  when 
for  the  better  apprehension  of  a  geometrical  theorem  we  con- 
struct a  diagram  on  paper,  we  trouble  ourselves  very  little  as  to 
its  perfect  proportions  ;  we  admit  without  difficulty  shaky  lines 
in  our  polygon,  and  irregular  curvature  in  our  circle.  In  fact, 
we  do  not  consider  the  circle  traced  on  the  paper;  it  is  not  the 
object,  but  the  aid  of  our  thought ;  by  its  means  we  conceive 
something  differing  from  it,  which  is  neither  black  nor  traced 
on  a  white  ground,  nor  of  any  particular  radius,  nor  of  unequal 
curvature. — What,  then,  is  this  object  we  conceive,  and  of  which 
experience  affords  us  no  model  ?  The  definition  tells  us.  A 
circle  is  a  closed  curve,  all  whose  points  are  equally  distant 
from  an  internal  point  called  the  centre. — But  what  have  we  in 
this  phrase  ?  Nothing,  except  a  series  of  abstract  words  which 
denote  the  genus  of  the  figure,  and  another  series  of  abstract 
words  which  denote  the  species  of  the  figure,  the  second  being 
combined  with  the  first,  as  a  condition  added  to  a  condition. 
In  other  terms,  an  abstract  character  denoted  by  the  first  words 
has  been  joined  to  an  abstract  character  denoted  by  the  second 
words,  and  the  total  compound  thus  constructed  denotes  a  new 
thing  to  which  our  senses  cannot  attain,  which  our  experience 
cannot  come  in  contact  with,  which  our  imagination  cannot 
trace.  There  is  no  necessity  for  our  attaining  to,  meeting  with, 
or  imagining  this  thing ;  we  have  its  formula,  and  that  is  enough. 

In  fact,  this  formula  would  be  rigorously  the  same  if  the 
object  had  fallen  within  our  experience.  We  have  constructed 
the  formula  before  instead  of  after  the  experience,  and  it  corre- 
sponds all  the  more  closely  to  the  thing,  since  the  thing  must 
bend  to  it — not  it  to  the  thing.  The  two  then  make  up  a 
couple  whose  second  term,  the  definition,  is  equivalent  to  the 
first  term,  that  is,  to  the  object. — This  object  may  remain 


26  OF  SIGNS.  [BOOK  I. 

ideal :  it  may  itself  be  situated  beyond  our  grasp ;  it  matters 
little  ;  we  have  its  representative.  Whatever  properties  and  re- 
lations we  find  in  the  substitute  we  shall  safely  ascribe  to  the 
thing  for  which  it  is  substituted.  We  arrive  at  this  indirectly,  as 
a  surveyor,  who,  wishing  to  measure  an  inaccessible  line, 
measures  a  base  and  two  angles,  and  knows  the  first  quantity 
by  the  three  second. — In  this  way  all  mathematical  concep- 
tions are  formed.  We  take  very  simple  abstractions,  the  surface 
which  is  the  limit  of  the  solid,  the  line  which  is  the  limit  of 
the  surface,  the  point  which  is  the  limit  of  the  line,  the  unit  or 
quality  of  being  one,  that  is  to  say,  distinct  existence  among 
similar  things.  We  combine  these  terms  together  and  form, 
first,  compounds  of  small  complexity,  those  of  two,  three,  four, 
and  the  earlier  numbers,  those  of  plus  and  minus,  of  greater 
and  less,  of  longer  and  shorter  lines  ;  then  those  of  straight  line 
and  curve,  of  triangle,  of  circle  ;  then,  those  of  sphere,  cone, 
cylinder,  and  the  rest.  The  complication  of  compounds  goes  on 
increasing;  it  is  unlimited.  Taken  together  they  form  a  king- 
dom apart  of  objects  which  have  no  real  existence,  but  which 
are  capable,  like  real  objects,  of  being  classed  in  families,  genera, 
species,  and  properties,  of  which  we  discover  by  considering  in 
their  place  the  properties  of  the  formulae  which  we  substitute 
for  them. 

By  a  strange  continuation  the  process  which  has  formed 
these  objects  is  also  that  which  establishes  their  relations. 
Arithmetic,  algebra,  geometry,  analytical  geometry,  mechanics, 
the  higher  calculus,  all  the  propositions  of  mathematical  science, 
are  substitutions.  Any  number  we  take  is  a  substitute  for  the 
preceding  number  added  to  unity.  To  calculate,  is  to  replace 
several  numbers  by  a  single  one  at  the  end  of  several  partial  re- 
placements. To  solve  an  equation,  is  to  substitute  terms  for  oth- 
er terms  with  the  object  of  arriving  at  a  final  substitution.  To 
measure,  is  to  replace  an  undetermined  magnitude  by  another 
magnitude  defined  in  its  relation  to  unity.  To  construct  a 
diagram  for  the  demonstration  of  a  theorem  is  to  substitute 
certain  known  lines  and  angles  for  other  lines  and  angles  which 
it  is  required  to  know.  To  find  the  algebraic  formula  of  a 
curve,  is  to  discover  mathematical  relation  between  certain 
lines  which  are  connected  with  the  curve,  and  to  translate  quality 


.  III.]  REPEATED   SUBSTITUTIONS.  27 

into  quantity. — However  we  may  reason  about  numbers  and 
magnitudes,  the  process  amounts  to  passing  from  one  equivalent 
to  another  equivalent  by  the  aid  of  a  series  of  intermediate 
equivalents,  to  replacing  magnitudes  by  numbers  expressing 
them,  a  figure  by  a  corresponding  equation,  a  complete  quan- 
tity by  a  quantity  in  process  of  completion,  having  the  .first  as 
limit,  movements  and  forces  by  lines  representing  them.  We 
pass  from  each  province  to  the  other  by  substitutions,  and. 
as  a  substitute  may  have  substitutes,  the  operation  has  no 
limits. 

III.  Leaving  for  the  moment  this  extension  of  our  process, 
let  us  consider  it  once  more  at  its  outset.  We  have  seen  how, 
by  combining  abstracts,  we  construct  the  first  terms  of  couples, 
the  second  terms  of  which  are  beyond  our  reach,  and  how,  by 
the  study  of  the  generating  formula,  we  discover  the  properties 
of  the  object  engendered  by  it.  In  certain  cases,  we  discover 
in  it  wonderful  properties,  and  the  formula  makes  known  to  us 
facts  situated  not  only  beyond  our  experience,  but  beyond  all 
experience. — If  we  divide  2  by  3,  we  find  an  infinite  decimal 
fraction,  0-6666,  etc.,  and  we  can  prove  that  it  is  infinite.  It  is 
strictly  so,  and  without  possible  break ;  however,  far  we  may 
prolong  the  operation,  the  remainder  will  always  be  2  and  the 
quotient  always  6.  After  a  million,  after  a  thousand  million, 
after  a  million  million  of  such  divisions,  new  terms  will  present 
themselves,  with  the  same  remainder  and  the  same  quotient," 
with  a  total  quotient  always  too  small,  to  small  by  a  fraction 
with  2  for  numerator,  and  for  denominator  unity  followed  by  as 
many  zeros  as  there  are  units  in  the  number  of  divisions  we  have 
made.  Here  is  something  infinite  ;  not  vague,  not  indefinite, 
but  precise,  which  is  expressly  opposed  to  any  limit,  and  so 
clearly  conceived  that  all  its  elements  have  their  distinct  and 
express  properties. — Does  this  mean  that  I  perceive  distinctly 
the  infinite  series  of  these  elements  ?  Certainly  not.  Here 
again,  there  is  a  substitute,  the  formula,  from  which  the  series 
and  the  properties  of  its  elements  are  derived.  What  we  per- 
ceive, is  a  general  character  of  the  dividend  and  remainder. 
After  the  first  division  we  can  see  that,  the  remainder  being  2 
like  the  dividend,  must,  in  becoming  in  its  turn  a  dividend,  give 
rise  again  to  a  remainder  2,  which  in  its  turn  will  do  the  same, 


28  OF  SIGNS.  [BOOK  I. 

and  so  on.  In  other  words,  we  discover  in  the  dividend  this 
property  of  giving  rise  to  a  similar  figure,  which,  being  similar 
to  it,  has  the  same  property  as  it.  This  abstract  quality  is  the 
cause  of  the  whole  series';  it  forces  it  to  be  infinite,  it  alone  is 
what  we  perceive ;  when  we  say  that  we  conceive  an  infinite 
series,  it  only  means  that  we  discover  this  property  of  inex- 
haustible regeneration  ;  all  we  seize  is  the  generating  law  ;  we 
do  not  embrace  all  the  engendered  terms. — But  as  far  as  we 
are  concerned  the  effect  is  the  same  ;  for  by  applying  the  law 
we  are  able  to  define  whatever  term  we  please  of  the  series,  to 
measure  exactly  the  increase  of  approximation  it  brings  to  the 
quotient,  to  calculate  strictly  the  degree  of  error  which  the 
division  would  include  were  we  to  stop  Jiere.  The  perception 
of  the  law  is  equivalent  to  the  perception  of  the  series ;  an  in- 
finite line  of  distinct  terms  finds  its  substitute  in  an  abstract 
character,  and,  in  place  of  an  experience  which  is  by  defini- 
tion impossible,  we  have  disengaged  a  property  whose  isola- 
tion has  only  required  two  experiences,  and  which  is  of  equal 
value  to  us. 

And  so  it  happens,  whenever  we  conceive  and  affirm  some 
really  infinite  abstract  magnitude,  time,  or  space.  We  take  a 
fragment,  some  short  portion  of  the  duration  comprised  in  our 
successive  sensations,  some  narrow  portion  of  space  comprised 
in  our  simultaneous  sensations.  We  consider  this  fragment 
'apart ;  we  extract  from  it  this  property  it  has  of  being  over-ex- 
tended by  a  border  absolutely  similar  to  itself.  We  lay  down, 
as  before,  a  general  law  that  the  magnitude  in  question  is  con- 
tinued beyond  itself  by  another  wholly  similar  magnitude,  and 
this  by  another,  and  so  on,  without  the  possible  intervention  of  a 
limit.  Our  conception  of  infinite  time  and  infinite  space  is  re- 
duced to  this. — But  the  result  is  the  same  as  if  the  field  of  our 
imagination  were  infinitely  extended  and  capable  of  setting  be- 
fore us  at  a  glance  the  whole  infinite  succession  we  call  time,  or 
the  extension,  infinite  in  three  directions,  which  we  call  space. 
For  starting  from  the  general  character  which  alone  is  present 
to  our  minds,  we  are  able  to  imagine  any  portion  of  time  or  space 
as  clearly,  and  to  affirm  of  it  as  surely,  as  if  we  had  experience 
of  it ;  no  matter  what  the  portion  be,  whether  a  fragment  of 
duration  preceding  the  solar  system,  or  a  portion  of  space  be- 


CHAP.  III.]  REPEA  TED   SUBSTITUTIONS. 


29 


yond  the  furthest  nebulas  of  Herschel.  It  is  possible,  then,  to 
represent  infinite  objects,  series,  or  quantities,*  by  an  abstract 
property.  It  is  enough  if  this  is  their  generator.  By  it,  indi- 
rectly, they  become  present.  Here  we  have,  I  think,  the  most 
extraordinary  example  of  substitution. — There  are  other  cases, 
analogous  but  reversed,  in  mathematics ;  certain  quantities, 
which  go  on  increasing  or  decreasing,  without  the  possibility 
of  a  limit,  replace  the  limit  which  they  necessarily  approach 
without  ever  touching  it.  A  polygon  with  an  infinite  number  of 
sidos  inscribed  in  a  circle  is  equivalent  to  the  circle.  The  frac- 
tional number  I  \  \  •§-,  etc.,  is  equivalent  to  the  num- 
ber 2.  Here  again,  as  before,  mathematicians  do  but  resume, 
extend,  or  reverse  a  spontaneous  process  of  the  mind. — The 
process  is  explainable  similarly,  whether  direct  or  reversed. 
Given  two  members  of  a  couple,  one  infinite,  the  other  limited, 
we  can  consider  at  will  the  one  or  the  other,  and  if  they  corre- 
spond strictly,  can  discover  in  the  one  properties  belonging  also 
to  the  other,  but  not  discoverable  in  it. 

IV.  To  recapitulate.  We  do  not  conceive  numbers,  with 
the  exception  of  the  three  or  four  earlier  ones,  but  their  equiv- 
alents, that  is  to  say,  the  name  of  the  preceding  number 
joined  to  unity ;  we  do  not  conceive  infinite  or  ideal  objects, 
but  the  abstract  characters  which  generate  them ;  we  do  not 
conceive  abstract  characters,  but  the  common  names  which  cor- 
respond to  them.  However  far  we  may  go,  we  always  come 
back  to  names.  Things  the  most  removed  from  our  experi- 
ence and  the  most  inaccessible  to  all  experience,  seem  present 
to  us ;  what  is  actually  present,  in  such  a  case,  is  a  name,  the 
substitute  of  an  abstract  character  which  is  itself  the  substitute 
of  the  thing,  and  this  often  only  through  many  intermediate 
stages,  till  at  last  by  a  series  of  equivalents  the  chain  re-touches 
the  distant  object  which  we  cannot  directly  reach. 

Hence  arise  singular  illusions.  We  believe  that,  in  addi- 
tion to  our  general  words,  we  possess  general  ideas ;  we  dis- 
tinguish the  idea  from  the  word ;  it  seems  to  us  something 
apart  from  the  word,  and  to  which  the  word  is  merely  auxili- 


*  When  we  speak  of  an  infinite  quantity,  it  is  by  extension  ;  strictly  speaking, 
a  quantity  is  always  finite,  and  there  is  nothing  infinite  but  series. 


3o  OF  SIGNS.  [BOOK  I. 

ary ;  we  compare  it  with  the  image,  and  pronounce  them  to 
fulfil  similar  offices  in  distinct  provinces,  and  that  ideas  bring 
present  to  us  general  things,  as  images  bring  present  individu- 
als. We  remark  with  Descartes,  that  we  can  readily  conceive 
a  myriagon  but  have  great  difficulty  in  imagining  it.  We  set 
on  one  side  the  intelligible  myriagon  and  the  corresponding 
precise  idea,  and,  in  contrast,  the  actual  myriagon  and  the  cor- 
responding confused  image.  We  then  observe  that  this  idea 
is  in  no  way  similar  to  the  image ;  except  in  its  employment ; 
it  brings  before  us  an  absent  thing  as  the  image  does,  but  that 
is  all.  It  has  no  other  properties  ;  it  is  not,  like  the  image,  an 
echo;  the  echo  of  a  sound,  a  smell,  a  color,  a  muscular  impres- 
sion, in  short,  the  internal  revival' of  some  sensation;  there  is 
nothing  sensible  about  it,  and  we  can  only  define  it  by  deny- 
ing of  it  all  sensible  qualities ;  it  seems  then  a  pure  activity 
stripped  of  all  other  qualities  but  that  of  bringing  the  myria- 
gon present  to  our  minds.  We  compare  it  to  something  in- 
tangible, unextended,  incorporeal ;  we  suppose  a  being  as  pure 
and  ethereal  as  itself  of  which  it  is  the  manifestation  ;  we  call 
it  mind,  and  say  that,  irrespective  of  images,  our  mind  knows 
and  deals  with  abstract  qualities  of  things. 

The  mechanism  of  this  illusion  may  now  be  readily  detect- 
ed. We  have  overlooked  the  word  which  is  the  whole  sub- 
stance of  our  operation;  we  have  treated  it  as  accessory  and 
have  considered  the  operation,  omitting  what  it  comprises ; 
hence  a  blank. — This  error  of  consciousness  is  of  frequent 
occurrence  and  may  be  traced  to  a  general  law.  When  an 
impression,  or  group  of  impressions,  is  many  times  repeated, 
our  attention  ends  by  fixing  itself  entirely  on  the  interesting 
and  useful  part ;  we  neglect  the  rest,  we  cease  to  notice  it,  we 
become  unconscious  of  it,  and  though  present,  it  seems  to  be 
absent.  So  it  is,  for  instance,  with  the  slight  muscular  sensa- 
tions occasioned  by  the  eye  adapting  itself  to  various  distan- 
ces ;  they  are  the  signs  of  these  distances,  and  by  them  we  de- 
termine the  degree  of  proximity  or  distance  of  objects.  We 
necessarily  have  these  sensations  when  we  judge  of  distances, 
but  we  cannot  detect  them,  even  if  we  wish  to.  To  us,  they 
are  as  if  they  did  not  exist ;  we  appear  to  know  directly,  and 
without  their  aid,  the  positions  which  they  alone  denote ; 


CHAP.  III.]  REPEATED   SUBSTITUTIONS.  3! 

if  ever  they  strike  us,  it  is  in  extreme  cases,  as  when  we  at- 
tempt to  read  something  at  a  distance,  or  inconveniently  near 
the  eye,  and  feel  sensible  fatigue  in  the  muscles  ;  except  in  such 
cases  they  are  invisible,  and  have,  as  it  were,  vanished. — So 
again,  a  composer  who  has  just  read  some  air  of  an  opera,  docs 
not  recall  the  crotchets,  quavers,  keys,  staves,  and  all  the  black 
hieroglyphics  over  which  his  eyes  have  passed,  but  only  the 
series  of  chords  which  he  has  heard  mentally ;  the  signs  are 
obliterated,  the  sounds  alone  survive. — When  words  are  in 
question,  we  can  trace  the  different  degrees  of  this  obliteration. 
The  meaning  of  a  page  in  manuscript  is  comprehended  with  far 
more  difficulty  than  that  of  a  printed  one ;  our  attention  is 
partly  attracted  by  the  external  form  of  the  characters,  in  place 
of  attaching  itself  solely  to  the  sense  they  bear;  we  observe 
the  individual  peculiarities  of  the  signs,  as  well  as  what  they 
are  employed  to  represent.  But  after  a  while,  these  peculiar- 
ities cease  to  strike  us ;  when  they  are  no  longer  new,  they  are 
no  longer  singular,  and  no  longer  singular,  are  no  longer 
observed ;  and  then,  in  the  manuscript  as  in  print,  we  seem 
no  longer  to  be  following  words,  but  pure  ideas. — We  see 
now  how  it  necessarily  happens,  that  in  our  reasonings,  and 
all  the  higher  operations  of  the  mind,  the  word,  though 
present,  is  unperceived.  From  the  train  of  our  discoveries 
we  conclude  that  we  have  acted,  and  produced  a  series  of 
acts,  that  this  series  corresponds  to  a  series  of  qualities,  or 
characters  of  things,  that  our  activity  is  effective,  and  therefore 
real.  What  then  can  we  affirm  of  this  internal  activity?  Noth- 
ing, except  that  it  is  activity;  by  the  disappearance  of  words 
we  have  exhausted  it  of  all  it  comprises ;  we  set  it  apart  pure 
and  simple,  or  as  we  say,  spiritual ;  having  stripped  it,  we  be- 
lieve it  to  be  naked ;  and  when,  later  on,  we  observe  that  to 
produce  it  we  have  made  use  of  signs,  we  conclude  that  the  sign 
is  but  a  preliminary  aid  to  it,  and  a  distinct  reminder  of  it. 
This  separation  and  nudity  are  of  our  own  effecting ;  they  do 
not  belong  to  it,  but  are  lent  it  by  us. 

This  is  the  first  of  psychological  illusions,  and  what  we  term 
consciousness  swarms  with  such.  The  false  theories  they  have 
given  rise  to  are  as  complex  as  they  are  many,  and  are  at  pres- 
ent obstructing  science.  When  they  are  cleared  away,  science 


22  OF  SIGNS.  [BOOK  I. 

will  become  simple  again. — Having  discarded  this  illusion,  we 
see  the  consequences.  What  we  have  in  our  minds  when  we 
conceive  general  qualities  and  characters  of  things,  are  signs 
and  signs  only.  I  mean  certain  images  or  revivals  of  sensations 
of  the  eye  or  ear,  wholly  similar  to  other  images,  except  in  their 
corresponding  to  characters  and  general  qualities  of  things,  and 
in  their  replacing  the  absent  or  impossible  perception  of  these 
characters  and  qualities. — Thus  when,  neglecting  present  sen- 
sations, we  observe  the  never-resting  inmates  of  our  mind,  we 
find  there  images  only,  some  prominent  ones  which  strike  the 
attention,  others  faded,  and  seemingly  worn  away  to  shadows, 
on  account  of  the  attention  being  diverted  from  them  to  their 
uses.  Here  we  have  an  element  of  knowledge  which  seemed 
primitive,  but  which  is  reduced  to  another.  We  must  now  at- 
tempt to  know  that  other.  Since  our  ideas  may  be  reduced  to 
images,  their  laws  may  be  reduced  to  laws  of  images ;  images 
then  are  what  we  must  study. 


CHAP.  L]      NATURE  AND  REDUCTION  OF  IMAGES  33 


BOOK    II. 

OF  IMAGES. 


CHAPTER  I. 

OF  THE  NATURE  AND  REDUCTION  OF  IMAGES. 

I.  YESTERDAY  evening,*  about  five,  I  was  on  the  quay  by 
the  Arsenal,  watching  in  front  of  me,  across  the. Seine,  the  sky 
reddened  by  the  setting  sun.  Fleecy  clouds  rose  in  the  form 
of  a  half  dome,  and  bent  over  the  trees  of  the  Jardin  des 
Plantes.  The  whole  of  this  vault  seemed  incrusted  with  scales 
of  copper;  countless  indentations,  some  almost  burning,  some 
nearly  black,  extended,  in  rows  of  strange  metallic  lustre,  up 
to  the  highest  part  of  the  sky,  while,  all  below,  a  long  bronze- 
colored  band,  extending  along  the  horizon,  was  streaked  and 
cut  by  a  black  fringe  of  branches.  Here  and  there,  rose-col- 
ored gleams  of  light  rested  on  the  pavements  ;  the  river 
shone  softly  through  a  rising  mist ;  I  could  see  barges  floating 
with  the  stream,  and  two  or  three  teams  of  horses  on  the 
bank,  while  towards  the  east,  the  slanting  beams  of  crane 
stood  out  against  the  gray  sky.  In  half  an  hour,  all  this  had 
died  out ;  there  was  but  one  patch  of  clear  sky  behind  the  Pan- 
theon ;  reddish-colored  smoke  was  wreathing  about  in  the  dying 
purple  of  the  evening,  and  the  vague  colors  intermingled.  A 
blue  vapor  hid  the  arches  of  the  bridges  and  the  edges  of  the 
roofs.  The  apse  of  the  cathedral  stood  alone,  looking  with 
its  pinnacles  and  jointed  buttresses,  in  size  and  shape  like  an 
empty  crab-shell.  Things  prominent  and  colored  but  a  mo- 
ment ago,  were  now  like  mere  sketches  on  a  dull  paper.  Here 
and  there  a  gas-light  shone  out  like  a  lonely  star,  and  caught 
the  attention  as  other  things  faded  away.  Soon,  strings  of  light 

*  24th  November,  1867. 


34  OF  IMAGES.  [BOOK  II. 

extended  themselves  as  far  as  the  eye  could  reach,  and  the  in- 
distinct flickering  glare  of  crowded  Paris  rose  in  the  west ;  while 
below  the  arches,  along  the  quays,  and  over  the  weirs,  the  rip- 
pling water  kept  up  its  nightly  murmuring. 

I  saw  this  yesterday ;  and  now  as  I  write  I  see  it  again — 
dimly,  it  is  true,  but  still  I  see  it.  The  colors,  forms,  sounds, 
which  struck  me  yesterday,  are  now  renewed,  or  nearly  so. 
Yesterday,  I  experienced  sensations  excited  by  the  immedi- 
ate contact  of  things  and  immediate  action  of  the  nerves. 
To-day  impressions  analogous  to  those  sensations,  though 
remotely  so,  arise  in  me,  notwithstanding  the  want  of  this  ac- 
tion and  contact,  notwithstanding  the  presence  of  other  ac- 
tions and  contacts.  It  is  a  semirevival  of  my  experience ;  dif- 
ferent terms  might  be  used  to  express  it,  we  might  call  it  an 
after-taste,  an  echo,  a  representation,  a  phantom,  an  image  of 
the  primitive  sensation ;  it  matters  little ;  all  these  compari- 
sons mean -no  more  than  that  after  a  sensation  excited  by 
the  outer  world,  and  not  spontaneous,  we  find  within  us  a 
second  event  corresponding  to  it,  which  is  spontaneous  and 
is  not  excited  by  the  outer  world,  which  resembles  the  sen- 
sation, and  is  accompanied,  though  not  so  forcibly,  with  the 
same  emotions,  which  is  pleasurable  or  the  reverse,  but  in  a 
less  degree,  and  is  followed  by  some,  but  not  all,  the  same 
mental  conclusions.  The  sensation  repeats  itself,  though 
with  less  distinctness  and  force,  and  deprived  of  many  of  its 
surroundings. 

This  obliteration  is  more  or  less  complete  according  to 
the  differences  of  men's  minds,  and  this  is  what  we  mean 
when  we  say  that  men  have  more  or  less  memory.  Again, 
it  is  more  or  less  complete  in  the  same  minds  according  to 
the  different  kinds  of  sensations,  and  this  is  what  is  meant 
by  saying  that  such  a  man  remembers  forms,  another  colors, 
another  sounds. — For  example,  in  my  own  case,  I  have  but 
an  ordinary  memory  for  forms  and  a  slightly  better  one  for 
colors.  I  can  see  without  difficulty  after  several  years  five 
or  six  fragments  of  an  object,  but  not  its  precise  and  com- 
plete outline  ;  I  can  recall  more  easily  the  whiteness  of  a 
sandy  path  at  Fontainebleau,  the  hundred  little  spots  and 
stripes  made  by  the  sprigs  of  wood  strewed  on  it,  its  winding 


CHAP.  I.]        NATURE  AND  REDUCTION  OF  IMAGES.  35 

curves,  the  faintly  rose-colored  tints  of  the  heather  by  its 
sides,  the  wretched  appearance  of  a  stunted  birch  clinging  to 
the  side  of  a  rock  ;  but  I  cannot  trace  in  my  mind  the  wind- 
ing of  the  path  or  the  jutting  out  of  the  rocks :  if  I  mentally 
catch  sight  of  the  swelling  of  some  vegetable  muscle  my  half- 
sight  stops  there  ;  above,  below,  all  is  vague  ;  even  involuntary 
revivals,  which  are  the  most  vivid,  are  only  half  clear  to  me ; 
the  most  visible  an  most  highly-colored  fragment  is  dull  and 
tame.  Compared  to  the  sensation  it  is  as  a  half-heard  whis- 
per to  an  articulate,  ringing  voice.  In  my  case,  all  that  is 
reproduced  uninjured  and  whole  is  the  precise  shade  of  emo- 
tion, harsh,  tender,  strange,  sweet,  or  sad,  which  followed 
or  accompanied  the  external  corporeal  sensation.  I  can  thus 
renew  my  pains  and  pleasures,  the  most  complex  and  most  del- 
icate, with  extreme  exactness  and  after  considerable  distances 
of  time.  In  this  respect,  the  incomplete  and  failing  whisper 
has  almost  the  same  effect  as  the  voice. — But  if,  instead  of 
taking  the  instance  of  a  man  inclined  to  pay  principal  at- 
tention to  sentiments,  we  look  at  men  accustomed  to  observe 
particular  colors  and  forms,  we  shall  find  cases  of  images  so 
clear  as  to  differ  little  from  sensations. 

For  example,  children  accustomed  to  calculate  in  their 
heads,  write  mentally  with  chalk  on  an  imaginary  board  the 
figures  in  question,  then  all  their  partial  operations,  then  the 
final  sum,  so  that  they  see  internally  the  different  lines  of 
white  figures  with  which  they  are  concerned.  The  remarka- 
ble children  who  are  precocious  mathematicians  give  a  simi- 
lar account  of  themselves.*  Young  Colborn,  who  had  never 
been  at  school,  and  did  not  know  how  to  read  or  write,  said 
that  when  making  his  calculations,  "  he  saw  them  clearly 
before  him."  Another  said  that  he  "saw  the  numbers  he 
was  working  with  as  if  they  had  been  written  on  a  slate. "- 
So  again,  we  find  chess-players  who  play  a  game  with  their 
eyes  closed,  and  faces  turned  towards  the  wall.  They  have 
numbered  the  squares  and  pieces;  at  each  move  of  their  op- 
ponent they  are  told  the  piece  moved  and  the  new  square  it 
occupies  ;  they  give  directions  themselves  for  the  movement 


*  Gall,  "  Fonctions  du  Cerveau,"  tome  v.  130. 


36  OF  IMAGES.  [BOOK  II. 

of  their  own  pieces,  and  go  on  in  this  way  for  many  hours. 
They  often  win,  even  when  opposed  to  skilful  players.  Evi- 
dently the  figure  of  the  whole  chess-board,  with  the  different 
pieces  in  order,  presents  itself  to  them  at  each  move,  as  in  an 
internal  mirror,  for  without  this  they  would  be  unable  to  fore- 
see the  probable  consequences  of  their  adversary's  and  their 
own  moves. 

An  American  friend  of  mine,  who  has  this  faculty,  de- 
scribes it  to  me  in  these  words  :  "  When  I  am  in  my  corner, 
facing  the  wall,  I  see  simultaneously  the  chess-board  and  all 
the  pieces,  as  they  were  in  reality  after  the  last  move.  And 
as.  each  piece  is  moved,  I  see  the  whole  chess-board  with  the 
new  change  effected.  If  I  am  in  doubt  in  my  mind  as  to 
the  exact  position  of  a  piece,  I  play  over,  mentally,  the  whole 
game  from  the  beginning,  attending  carefully  to  the  success- 
ive movements  of  that  piece.  It  is  far  easier  to  deceive  me 
when  I  watch  the  board  than  otherwise ;  in  fact,  when  I 
am  in  my  corner,  I  defy  any  one  to  mislead  me  as  to  the  po- 
tion of  a  piece  without  my  afterwards  detecting  it I 

see  the  piece,  the  square,  and  the  color,  exactly  as  the  work- 
man made  them — that  is,  I  see  the  chess-board  standing  be- 
fore my  adversary,  or  at  all  events,  I  have  an  exact  represen- 
tation of  it,  and  not  that  of  another  chess-board.  So  far  is 
this  the  case  that,  before  retiring  to  the  corner,  I  begin  by 
carefully  looking  at  the  chess-board  and  men  as  they  stand, 
and  to  this  first  impression  I  mentally  attend  and  revert." 
Usually,  he  does  not  see  the  table-cloth  nor  the  shadows  of 
the  pieces,  nor  the  minute  peculiarities  of  their  make,  but 
can  recall  them  if  he  wishes.  He  has  often  played  chess 
with  a  friend  who  has  also  this  faculty,  while  walking  along 
the  quays  or  in  the  streets. — As  might  be  expected,  so  exact 
and  intense  a  representation  is  repeated  and  lasts  involunta- 
rily. "  I  have  never  played  a  game,"  says  he,  "  without 
having  played  it  over  again  four  or  five  times  in  flie  night  in 
bed,  with  my  head  on  the  pillow When  I  am  sleep- 
less and  have  unpleasant  thoughts,  I  set  myself  to  play  at 
chess,  imagining  a  game,  with  all  the  pieces,  and  this  occu- 
pies my  mind  and  drives  away  the  besetting  thoughts." — 
The  first  players  are  not  the  most  skilful  at  this  artifice.  La- 


CHAP.  I.]        NATURE  AND  REDUCTION  OF  IMAGES.  37 

bourdonnais  could  only  play  two  games  at  once,  mentally ; 
having  once  attempted  three  at  a  time  he  died  from  the  ef- 
fort. "  It  is  not  unusual  to  find  in  clubs,  fourth-rate  players 
who  wake  up  some  morning  with  this  faculty." — Some  of 
them  attain  an  extent  and  clearness  of  imagination  which 
are  simply  marvellous.  "  Paul  Morphy  plays  eight  games  at 
a  time,  and  Paulsens  twenty.  This  I  have  seen  myself." — 
Other  images,  far  more  irregular  and  with  more  variety  of 
shade,  and  so,  it  would  seem,  more  difficult  to  recall,  pre- 
sent themselves  with  equal  precision.  Certain  painters, 
draughtsmen,  and  sculptors,  after  attentively  considering  a 
figure,  are  able  to  draw  it  from  memory.  Gustave  Ejore 
has  this  faculty;  Horace  Vernet  had  it.  Abercrombie*  men- 
tions a  painter  who  copied  from  recollection  and  without  the 
aid  of  an  engraving,  a  Martyrdom  of  Saint  Peter,  by  Ru- 
bens, with  so  perfect  an  imitation  that  the  two  pictures,  be- 
ing placed  beside  one  another,  considerable  attention  was  re- 
quired to  distinguish  the  copy  from  the  original. 

We  can  follow  the  different  stages  by  which  the  ordinary 
image  passes  to  this  height  of  clearness  and  detail.  In  a  school 
of  art  at  Paris,  the  pupils  were  practised  in  copying  models 
from  memoiy.  After  four  months'  practice  they  said  that "  the 
image  "  had  become  "much  more  distinct,  and  if  it  disappears 
they  can  recall  it  almost  at  will." — M.  Brierre  de  Boismont,f 
having  studiously  impressed  on  his  mind  the  figure  of  a  priest 
of  his  acquaintance,  says,  "  At  present  this  mental  representa- 
tion is  visible  to  me,  whether  my  eyes  be  shut  or  open."  The 
image  appeared  to  him  "  external,"  placed  in  front  of  him  "  in 

the  direction  of  the  visual  ray It  has  the  size  and 

characters  of  the  original;  I  can  distinguish  his  features,  the 
cut  of  his  hair,  the  expression  of  his  face,  his  dress,  and  all  the 
details  of  his  person.  I  see  him  smile,  speak,  preach  ;  I  mark 

even  his  habitual  gestures The  image  is  shadowy  and 

of  a  different  nature  from  the  objective  sensation but 


*  '•  Inquiries  concerning  the  Intellectual,  Powers,"  p.  126  ;  and  see  Brierre  de 
Boismont,  "  Des  Hallucinations,"  pp.  449  et  seq.,  26  et  seq.,  where  many  analogous 
cases  are  collected.  See  also  "  Annales  Medico-Psychologiques,"  3me  Serie,  ii.  295. 

f  Op.  cit.  449 ;  and  De  Boisbaudran,  "  Education  de  la  Memoire  Pittoresque," 

pp.  77  and  83. 


38  OF  IMAGES.  [BOOK  II. 

clearly  outlined  and  colored,"  and,  saving  this  distinction  of  na- 
ture, provided  with  all  the  characters  belonging  to  the  real  per- 
son, or,  more  precisely,  with  all  the  characters  which  belong  to 
the  sensation  experienced  in  the  presence  of  the  real  person. — 
We  may  confidently  assert  then,  that  the  internal  event,  which 
we  call  a  sensation,  and  which  is  produced  in  us  when  our 
nerves,  and  consequently  our  brain,  receive  an  impression  from 
without,  is  reproduced  in  us  without  impression  from  without 
— in  the  majority  of  cases  partially,  feebly,  and  vaguely,  but  in 
many  cases  with  greater  clearness  and  force ;  in  some  cases 
with  a  precision  and  detail  nearly  equivalent  to  what  we  find 
in  the  sensation. 

The  sensations  of  hearing,  of  taste,  of  smell,  of  touch,  and, 
in  general,  all  sensations,  whatever  be  the  nerve  by  whose  ac- 
tion they  are  excited,  have  their  images.  We  can  all  of  us 
hear  tunes  mentally,  and  in  some  cases  the  image  is  not  far 
removed  from  the  sensation.  Just  now,  thinking  over  a  rep- 
resentation of  the  "  Prophet c"  I  repeated  silently  to  myselt 
the  pastorale  from  the  overture,  and  followed,  I  venture  to 
say  almost  felt,  not  only  the  order  of  the  notes,  their  different 
height,  rests,  and  lengths,  not  only  the  musical  phrase  re- 
peated as  an  echo,  but  also  the  keen,  piercing  tone  of  the 
hautboy  which  plays  it ;  its  sharp  drawn-out  notes  of  so  rus- 
tic a  harshness  that  the  nerves  are  startled,  and  filled  with  a 
rough  pleasure,  as  at  the  taste  of  raw  wine. — Every  good  musi- 
cian experiences  this  sensation  at  will,  when  he  follows  the  lines 
of  music  covered  with  their  black  marks.  The  leader  of  an 
orchestra,*  questioned  by  M.  Buchez,  told  him  that  when  he 
looked  over  a  score  "  he  heard  as  in  his  ear  "  not  only  the 
chords  and  their  succession,  but  also  the  tone  of  the  instru- 
ments. On  the  first  reading  over,  he  distinguished  the  quartet ; 
at  the  second  and  succeeding  ones,  he  added  to  the  quartet 
the  other  instruments ;  and  finally  he  perceived  and  appre- 
ciated distinctly  the  effect  of  the  whole. — Great  musicians 
have  this  gift  of  internal  hearing  in  an  eminent  degree.  It 
is  well  known  that  Mozart,  having  twice  heard  the  Miserere  of 
the  Sistine  Chapel,  wrote  it  down  entirely  from  memory.  As 


*  Brierre  de  Boismont,  op.  cit.  459. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  39 

it  was  forbidden  to  copy  it,  the  fidelity  of  the  master  of  the 
chapel  was  suspected,  on  account  of  the  difficulty  of  the  ex- 
ploit.* Mozart,  no  doubt,  on  his  return  home,  found  in  his 
mind,  when  seated  at  his  table,  as  if  in  a  minutely  exact 
echo,  these  lamentations  composed  of  so  many  parts  and 
carried  over  a  series  of  notes  so  strange  and  delicate.  When 
Beethoven  composed  many  of  his  great  works  after  he  had  be- 
come completely  deaf,  the  combinations  of  notes  and  tones 
which  we  now  admire  in  them  were  present  to  him.  They 
were  necessarily  present,  since  he  measured  their  effect  be- 
forehand, and  measured  it  with  rigorous  precision. 

II.  This  close  resemblance  of  the  image  and  sensation  be- 
comes clearer  still  if  we  consider  the  circumstances  under  which 
the  higher  degrees  of  intensity  of  the  image  occur. — A  first  ex- 
citant is  the  extreme  nearness  of  the  sensation.  When  we  have 
heard  a  full  striking  tone,  for  example,  the  rich  prolonged  note 
of  the  violoncello,  clarionet,  or  horn,  if  the  sound  suddenly 
ceases,  we  continue  for  some  seconds  to  hear  it  mentally ;  and, 
though  at  the  end  of  these  seconds  its  image  becomes  feeble 
and  obscure,  we  continue,  if  we  derived  any  pleasure  from  it, 
to  repeat  it  internally  with  remarkable  fidelity,  and  without 
letting  go  any 'portion  scarcely  of  smooth  or  striking  sound. 
And  so,  when  we  shut  our  eyes  after  having  regarded  attentive- 
ly any  object,  a  figure  in  a  print,  the  back  of  a  book  in  a  library, 
the  perception,  which  has  become  internal,  continues  for  nearly 
a  second,  then  disappears,  then  renews  itself,  but  softened ; 
then  is  troubled  and  fails  utterly,  without  leaving  any  other 
trace  than  a  vague  outline ;  and  the  losses  which  the  image 
has  undergone  prove  by  their  contrast  the  force  it  had  to  com- 
mence with.  So  it  is  after  a  smell,  a  taste,  an  impression  of 
cold,  of  heat,  of  local  pain,  and  the  rest. — If  the  sensation,  in- 
stead of  preceding,  is  about  to  follow,  the  effect  is  the  same. 
A  gourmand  seated  before  a  savory  dish,  the  steam  of  which 
is  rising  under  his  nose,  and  into  which  he  has  already  put  his 
fork,  tastes  beforehand  its  exquisite  flavor,  and  the  glands  of 
his  tongue  become  moistened  ;  the  image  of  the  expected  fla- 


*  It  is  necessary  to  have  heard  this  Miserere,  to  appreciate  the  capacity  and 
precision  of  such  memory  for  music. 


40  OF  IMAGES.  [BOOK  II. 

vor  is  equivalent  to  the  sensation  of  the  actual  flavor ;  the  resem- 
blance is  carried  so  far  that  the  salivary  glands  are  equally  ex- 
cited in  either  case.  This  is  why  a  physiologist,  who  wishes 
to  obtain  a  quantity  of  saliva  to  experiment  with,  ties  up  a 
hungry  dog  a  few  inches  from  a  piece  of  meat,  and  collects  the 
liquid  which  the  flavor  continually  wished  for  and  continually 
absent  discharges  from  the  animal's  jaws.  So  by  an  analogous 
but  contrary  effect,  any  thing  unpleasant  we  are  obliged  to  take 
excites  vomiting  by  the  simple  thought  of  its  taste  before  it 
touches  our  lips.  So  again,  a  ticklish  person  whom  we  threaten 
to  tickle,  and  who  sees  our  hand  approaching,  imagines  so 
strongly  the  coming  sensation,  that  he  has  spasmodic  feelings, 
the  same  feelings,  in  fact,  as  if  the  sensation  had  taken  place. 
Many  persons  who  are  about  to  undergo  a  surgical  operation, 
feel  beforehand  the  shooting  pain  which  will  follow  the  first 
cut,  and  sweat  and  grow  pale  at  the  very  thought,  and  some- 
times suffer  as  keenly  as  when  under  the  saw  and  knife.  A 
lady*  who  thought  she  was  inhaling  nitrous  oxide,  and  who 
had  simply  a  bottle  of  common  atmospheric  air  under  her  nose, 
fell  in  a  fainting  fit.  These  examples  show  us  also  that  the  im- 
portance of  the  sensation  is  another  excitant  as  powerful  to 
strengthen  the  image  as  the  proximity  of  the  sensation.  A 
traveller  in  Abyssiniaf  saw  one  of  his  men  torn  by  a  lion  ;  many 
years  afterwards,  when  he  thought  of  the  circumstance,  he  could 
hear  mentally  the  cries  of  the  unhappy  man,  "  and  felt  as  if  a 
hot  iron  were  entering  his  ear."  Numbers  of  mystics:}:  have 
represented  to  themselves  the  passion  of  our  Lord  with  such 
force,  that  they  have  believed  themselves  to  feel  in  their  bodies 
the  rending  and  pain  of  the  Saviour's  wounds. — Every  one 
knows  the  power  of  an  image,  especially  when  strange  and  ter- 
rible, upon  an  excited  and  prepared  mind  :  it  is  mistaken  for  a 
sensation,  and  the  illusion  is  complete.  Children,  and  even 
grown  men,  have  fallen  insensible  before  a  figure,  or  even  a  cloth, 
which  they  have  believed  to  be  a  ghost.  On  recovering,  they 
have  asserted  that  they  saw  flaming  eyes,  open  jaws. — In  all 
these  cases  the  image  has  in  no  way  differed,  for  the  time  at 

*  Mueller,  "  Elements  of  Physiology,  "  tr.  Baly,  ii.  1392. 

f  Brierre  de  Boismont,  op.  cit.  468. 

\  Maury,  "  La  Magie  et  1'Astrologie,  etc.,"  2me  partie,  chap.  iii.  passim. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES,  ^i 

least,  from  the  corresponding  sensation,  and  it  is  only  after  the 
lapse  of  a  longer  or  shorter  time,  when  the  recollection  has  sub- 
sided, and  the  circumstances  have  been  looked  into,  that  the 
deceived  person  has  recognized  his  mistake. 

III.  Hitherto  we  have  seen  the  image  approximating  to 
the  sensation,  acquiring  the  same  clearness,  the  same  abun- 
dance of  minute  and  circumstantial  detail,  the  same  force, 
sometimes  even  the  same  persistence,  furnishing  the  same 
foundation  for  higher  combinations  and  ulterior  reasonings, 
exciting  the  same  impressions  and  same  instinctive  actions, 
organic  and  muscular,  having  in  short  the  same  properties,  the 
same  accompaniments,  and  same  consequents  as  the  sensa- 
tion, without,  however,  being  wholly  and  definitely  confound- 
ed with  it.  In  fact,  there  remains  a  character  which  is  dis- 
tinctive to  the  image :  we  soon  recognize  it  as  internal,  we 
say  to  ourselves,  at  least  after  a  moment,  that  the  thing  thus 
sent  or  felt  is  but  a  phantom  ;  that  our  hearing,  our  sight,  our 
taste,  or  our  smell,  have  experenced  no  real  sensation.  We  are 
not  under  the  influence  of  hallucinations  ;  we  do  not  say — as 
sick  people  sometimes  do* — "  I  saw  and  heard  it  as  plainly  as  I 

now  see  and  hear  you I  assure  you  that  what  I 

saw  was  as  clear  as  the  day ;  and,  if  I  doubt  it,  I  must  also 
doubt  that  I  see  and  hear  you." 

To  explain  so  important  a  difference,  we  must  observe 
closely  in  what  the  recognition  of  an  illusion  consists.  There 
are  two  moments  during  the  presence  of  the  image  ;  one  affirm- 
ative, the  other  negative  ;  the  second  partially  qualifying  what 
the  first  began  to  affirm.  In  the  case  of  a  very  precise  and  in- 
tense image,  these  two  moments  are  very  distinct :  at  the 
first  it  seems  external,  situated  at  such  and  such  a  distance 
from  us,  when  a  sound  or  visible  object  is  in  question ;  situ- 
ated in  our  palate,  nose,  or  limbs,  when  a  sensation  of  smell, 
taste,  local  pain  or  pleasure  is  in  question.  "  The  exercise 
both  of  conception  and  imagination,"!  savs  Dugald  Stewart, 
"  is  always  accompanied  with  a  belief  (at  all  events,  momenta- 
ry) that  their  object  exists There  are  few  persons 

who  can  look  down  from  the  battlements  of  a  very  high  tower 

*  Baillarger,  "  Des  Hallucinations,"  374. 

f  "  Philosophy  of  the  Human  Mind,"  chap.  3,  i.  150-1.     Ed.  Hamilton. 


42  OF  IMAGES.  [BOOK  II. 

without  fear,  while  their  reason  convinces  them  that  they  are 
in  no  more  danger  than  when  standing  on  the  ground."  In 
fact,  when  we  look  directly  down  to  the  ground,  we  imagine 
ourselves  suddenly  taken  and  thrown  to  the  bottom ;  and 
this  image  alone  is  enough  to  make  us  shudder,  since,  for  an 
imperceptible  instant,  it  has  the  force  of  a  belief;  we  draw 
back  instinctively,  as  if  we  actually  felt  ourselves  falling.  We 
must  admit,  then,  that  "  whenever  the  objects  of  imagination 
engross  the  attention  wholly,  they  produce  a  temporary  be- 
lief of  their  reality."  This  is  why  persons  who  experience 
very  vivid  images  employ,  to  describe  them,  the  same  words 
as  to  denote  the  actual  sensation  ;  and,  during  some  seconds, 
take  their  images  for  sensations.  "  I  once  heard,"  says  Lie- 
ber,  "  a  colored  preacher  describing  the  torments  of  future 
punishment.  He  rose,  not  ineloquently,  from  the  description 
of  one  anguish  to  another,  when  at  last,  carried  away  by  un- 
controllable excitement,  he  merely  uttered,  for  more  than  a 
minute,  a  succession  of  inarticulate  sounds  or  cries."*  No 
doubt,  during  the  minute  in  question,  his  mental  vision  had 
all  the  characters  of  physical  vision.  He  had  before  him  an  im- 
aginary hell  resembling  a  real  hell,  and  he  believed  in  his  in- 
ternal phantoms  as  in  real  facts.  "  My  imaginary  persons," 
writes  the  clearest  and  most  accurate  of  modern  novelists, 
"  affect  me,  pursue  me,  in  fact,  I  live  in  them.  When  I  was  de- 
scribing the  poisoning  of  Emma  Bovary  I  had  so  strong  a  taste 
of  arsenic  in  my  mouth,  I  was  myself  so  far  poisoned,  that 
I  had  two  consecutive  fits  of  indigestion,  and  real  indigestion, 
for  I  threw  up  my  dinner." 

An  English  painter,  f  whose  rapidity  of  execution  was  mar- 
vellous, explained  his  mode  of  work  in  this  way ;  "  When  a 
sitter  came,  I  looked  at  him  attentively  for  half  an  hour,  sketch- 
ing from  time  to  time  on  the  canvas.  I  wanted  no  more — I  put 
away  my  canvas,  and  took  another  sitter.  When  I  wished  to 
resume  my  first  portrait,  /  took  the  man  and  sat  him  in  the 
chair,  where  I  saw  him  as  distinctly  as  if  he  had  been  before 
me  in  his  own  proper  person — I  may  almost  say  more  vividly.  I 


*  "  Smithsonian  Contributions  to  Knowledge,"  vol.  ii.  p.  9. 

f  Wigan,  "  A  New  View  of  Insanity.     The  Duality  of  the  Mind,  etc.,"  p.  124. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  43 

looked  from  time  to  time  at  the  imaginary  figure,  then  worked 
with  my  pencil,  then  referred  to  the  countenance,  and  so  on, 
just  as  I  should  have  done  had  the  sitter  been  there — when 
I  looked  at  the  chair  I  saw  the  man.  Gradually  I  began  to 
lose  the  distinction  between  the  imaginary  figure  and  the  real 
person ;  and  sometimes  disputed  with  sitters  that  they  had 
been  with  me  the  day  before.  At  last  I  was  sure  of  it; 

and  then — all  is  confusion I  lost  my  senses,  and  was 

thirty  years  in  an  asylum."  When  he  left  the  asylum  he 
had  still  the  power  of  painting  a  portrait  from  his  internal 
image  of  the  model,  but  was  persuaded  not  to  work  for  fear 
of  a  return  of  the  madness. 

The  chess-player  I  have  mentioned,  writes  again  :  "  I  never 
think  of  distinguishing  between  my  mental  chess-board  and 
the  actual  one.  As  far  as  I  am  concerned,  they  are  one ;  and  I 
could  only  establish  a  distinction  between  them  by  an  effort 
of  reasoning,  the  utility  of  which  I  have  never  experienced." 
Thus,  while  he  is  playing,  his  mental  chess-board  stands  to  him 
in  place  of  the  actual  one. — In  other  cases,  morbid  or  quasi- 
morbid,  we  see  the  image  acquire  complete  and  definite  ex- 
ternality. "  Recently,"  says  M.  Maury,*  "  my  eyes  were  at- 
tracted by  a  dish  of  very  scarlet  cherries  which  were  served  at 
my  table.  Just  after  dinner,  the  weather  grew  stormy,  and  the 
air  very  close  ;  I  felt  sleep  coming  over  me,  my  eyes  closed  ;  I 
was  then  thinking  of  the  cherries,  and  saw  in  a  sleepy  halluci- 
nation these  same  scarlet  cherries,  lying  on  the  same  green 
porcelain  dish  on  which  they  had  appeared  at  dessert.  Here 
was  a  direct  transformation  of  my  thought  into  sensation." 
Writers  on  insanity  mention  many  instances  of  similar  trans- 
formations, f  "  A  young  man  who  suffered  from  epilepsy, 
every  fit  of  which  was  preceded  by  the  apparition  of  an  indented 
wheel,  with  a  horrible  figure  in  the  middle,  assured  me  that 
he  had  the  power  of  producing  hallucinations.  He  amused 
himself  by  conceiving  some  strange  object  to  be  present ; 


*  "  Le  Sommeil,  et  les  reves,"  240. 

f  "  Annales  Medico-Psychologiques,"  3me  Serie,  ii.  389, 390,  M.  Michea — Cases 
collected  by  Abercrombie,  M.  Moreau,  Maisonneuve,  etc. — See  also,  Baillarger, 
"  Des  Hallucinations,"  "  Memories  de  1'Acadumie  de  Medecine,"  tome  xiii.  p. 
250. 


44  OF  IMAGES.  [BOOK  II. 

and  scarcely  had  he  formed  it  in  imagination  before  it  ap- 
peared accurately  before  his  eyes.  I  have  myself  seen  an  in- 
stance of  this  kind  in  a  monomaniac,  a  man  of  cultivated  mind 
and  perfect  sincerity  of  character,  who  assured  me  that  he 
had  but  to  recall  to  his  mind  or  to  imagine  a  person  or  thing, 
for  the  person  or  thing  to  appear  at  once  before  him  with 
every  appearance  of  externality." 

There  is  no  need  to  be  ill  or  half  asleep  to  watch  the  met- 
amorphosis by  which  the  image  projects  itself  from  within  to 
an  external  position.  "  A  friend  of  mind,"  says  Abercrombie,* 
"  had  been  one  day  looking  intensely  at  a  small  print  of  the 
Virgin  and  Child,  and  had  sat  bending  over  it  for  some  time. 
On  raising  his  head  he  was  startled  by  perceiving  at  the  farther 
end  of  the  apartment  a  female  figure  of  the  size  of  life,  with  a 
child  in  her  arms.  The  first  feeling  of  surprise  having  sub- 
sided, he  instantly  traced  the  source  of  the  illusion,  and  re- 
marked that  the  figure  corresponded  exactly  with  that  which 
he  had  contemplated  in  the  print.  The  illusion  continued 
distinct  for  about  two  minutes. "f  Goethe  was  able  to  pro- 
duce in  himself  a  complete  illusion  at  will.  "When  I  closed 
my  eyes,"  he  says,  "  and  depressed  my  head,  I  could  cause 
the  image  of  a  flower  to  appear  in  the  middle  of  the  field  of 
vision ;  this  flower  did  not  for  a  moment  retain  its  first  form, 
but  unfolded  itself,  and  developed  from  its  interior  new  flow- 
ers, formed  of  colored  or  sometimes  green  leaves.  These 
were  not  natural  flowers,  but  of  fantastic  forms,  although  sym- 
metrical as  the  rosettes  of  sculptors.  I  was  unable  to  fix  any 
one  form,  but  the  development  of  new  flowers  continued  as 


*  Op.  cit.  p.  63. 

f  Griesinger,  "Traite  des  Malades  Mentales"  (translation  by  Doumic),  p.  104  : 
"  Some  observers  are  able  to  produce  hallucinations  at  will ;  that  is  to  say,  ideas 
existing  in  their  consciousness,  and  on  which  they  firmly  direct  their  attention,  call 
into  play  the  sensorial  functions.  A  person  who  suffered  from  hallucinations  of 
hearing  observed  that  he  could  produce  the  voices  himself,  and  said  afterwards  that 
this  partly  assisted  him  in  recognizing  the  error.  M.  Sandras  speaks  of  hallucina- 
tions he  himself  suffered  from  during  an  illness  in  which  he  mistook  his  own  thoughts 
and  wishes  for  voices.  These  voices  answered  his  mental  questions  as  a  person  pres- 
ent would  have  done,  but  always  in  accordance  with  his  wishes. 

"  We  consider  the  phenomena  of  imagination  as  among  the  functions  of  the  inter- 
nal sensorial  apparatus,  and  as  differing  from  its  other  functions  in  intensity  only." 


CHAP. I.]        NATURE  AND  REDUCTION  OF  IMAGES.  A? 

long  as  I  desired  it,  without  any  variation  in  the  rapidity  of 
the  changes.  The  same  thing  occurred  when  I  figured  to  my- 
self a  variegated  disk.  The  colored  figures  upon  it  under- 
went constant  changes,  which  extended  progressively,  from 
the  centre  towards  the  periphery,  exactly  like  the  changes  in 
the  modern  kaleidoscope." — Finally,  hallucinations,  that  is  to 
say,  projections  into  the  outer  world  of  simple  mental  im- 
ages, have  been  produced,  not  only  in  full  health,  but  with 
the  complete  exercise,  and,  indeed,  by  the  exercise  of  the  will. 
"  A  German  writer  on  insanity,  Dr.  Brosius,  of  Bendorf,  men- 
tions his  having  produced  at  will  his  own  figure,  which  stood 
before  him  for  some  seconds,  but  which  vanished  immediate- 
ly he  attempted  to  fix  his  mind  on  his  personal  existence."* 

These  ^extreme  cases  show  by  their  exaggeration  the  na- 
ture of  the  normal  state.  Just  as  by  dissecting  an  hypertro- 
phied  stomach  we  succeed  in  distinguishing  dispositions  of  the 
muscular  fibres  which  are  invisible  in  a  healthy  stomach,  so 
by  examining  prolonged  illusions,  which  lasts  for  seconds, 
minutes,  or  more,  we  discover  the  existence  of  fugitive  illu- 
sions, accompanying  ordinary  images,  but  so  rapid,  short,  and 
instantaneous,  that  we  cannot  isolate  or  observe  them  directly. 
—This  illusion  is  none  the  less  real,  and  the  simple  analysis 
of  the  words  we  use  to  denote  the  image  bears  witness  to  the 
double  operation  by  which  it  is  formed.  We  say  that  such 
an  image,  a  phantom  of  hearing  or  sight,  of  taste  or  smell, 
which  seems  to  be  situated  either  in  some  part  of  our  or- 
gans, or  without  us,  seems,  erroneously,  to  be  situated  there, 
since  it  is  not  there  or  without  us,  but  internal.  This  phrase 
itself  indicates  the  recognition  and  correction  of  an  error, 
therefore  of  a  preliminary  error;  we  must  have  been  deceived, 
for  the  moment,  since,  a  moment  afterwards,  we  find  out 
the  mistake.  The  two  operations,  illusion  and  its  rectifica- 
tion, follow  so  closely  that  they  are  confused  into  one.  But 
suppress  the  rectification,  the  first  operation,  illusion,  will  alone 


*  "  Annales  Medico-Psychologiques,"  ibid. — I  have  myself  had,  in  a  dream  it  is 
true,  a  vision  of  this  kind  (November,  1869).  At  the  end  of  a  dream,  too  long  for 
narration,  my  own  figure  appeared  seated  in  an  arm-chair  near  a  table,  in  a  white 
dressing-gown  striped  with  black ;  it  turned  towards  me,  and  the  shock  was  so 
great  that  I  woke  up  with  a  start. 


46  OF  IMAGES.  [BOOK  II. 

remain,  and  its  unaccustomed  presence,  when  the  couple  is 
dissolved,  will  show  us  its  fugitive  presence  in  the  couple 
when  intact. 

IV.  This  leads  us  to  the  consideration  of  cases  in  which  the 
rectification  cannot  be  effected.  What  usually  effects  it  is  the 
presence  of  a  contradictory  sensation.  When  the  chess-play- 
er imagines  a  black  and  white  chess-board  two  paces  in  front 
of  him,  and  a  moment  afterwards  his  open  eyes  give  him  the 
sensation  of  a  gray  or  dark  wall  at  the  same  distance,  and  in 
the  same  direction,  the  sensation  and  image  cannot  co-exist. 
When  the  novelist  imagines  the  crushing  of  moistened  arsen- 
ic in  his  mouth,  and  "  the  horrible  inky  taste  "  which  the  poi- 
son leaves,  if,  a  moment  afterwards,  he  takes  a  mouthful  of 
wine  or  a  lump  of  sugar,  the  real  and  imaginary  sensations  ex- 
clude one  another,  and  the  momentary  illusion  caused  by 
the  image  disappears  under  the  ascendancy  of  the  sensation. 
And  thus  it  is  that  in  most  instances  the  passing  error,  con- 
nected for  a  moment  with  the  presence  of  the  image,  disap- 
pears, if  not  at  the  same  instant,  without  any  appreciable  in- 
terval elapsing,  by  the  opposing  shock  of  the  real  sensation. — 
Let  us  look,  then,  for  a  case  in  which  the  sensation  disap- 
pears and  becomes  as  it  were  absent ;  we  find  such  a  case  in 
the  reverie  preceding  sleep.*  The  sensations  produced  in 
us  by  the  external  world  are  then  effaced  by  degrees  ;  at  last 
they  seem  suspended,  and  the  images,  no  longer  distinguished 
from  sensations,  become  complete  hallucinations.  M.  Maury 
succeeded,  by  having  himself  awakened  at  intervals,  in  observ- 
ing a  great  number  of  them  :  for  example,  once,  when  sudden- 
ly roused  up,  "  I  saw  my  name  very  distinctly  on  a  sheet  of 
white  paper,  shining  like  the  very  smoothest  English  paper." 
He  seated  himself  again  in  his  easy-chair.  "  My  head  had 
scarcely  sunk  down  before  the  hallucination  returned  ;  but 
now,  instead  of  my  name,  I  saw  Greek  letters  and  words  which 
I  spelt  out  mechanically,  and  almost  with  a  movement  of  the 
lips.  On  several  successive  days  I  had,  whether  in  bed  or  my 


*  Maury,  "  Annales  Medico-Psychologiques,"  3me  Serie,  iii.  161. — And  "Le 
Sommefl  et  les  Reves,"  chap.  iv.  M.  Maury  was  the  first  to  show,  by  a  well-con- 
nected series  of  experiments,  the  near  relationship  of  the  sensation,  the  recollec- 
tion, the  image,  and  the  hallucination. 


CHAP  L]      NATURE  AND  REDUCTION  OF  IMAGES. 


47 


chair,  similar  hallucinations  or  real  dreams,  in  which  I  appeared 
to  be  reading  Oriental  characters.  This  reading  of  a  word  here 
and  there  was  always  accompanied  by  a  feeling  of  fatigue  in 
the  eyes.  .  .  .  Once,  above  all,  I  saw  Sanscrit  characters 
ranged  in  columns,  according  to  the  classification  of  gramma- 
rians, and  these  letters  had  a  relief  and  a  brilliancy  which  tired 
me.  It  must  be  observed  that  I  had  for  some  days  been  read- 
ing a  number  of  grammars  of  Asiatic  languages,  and  that  the 
fatigue  of  my  eyes  was  partly  owing  to  this  prolonged  reading." 
Here  we  not  only  have  the  image  which  has  become  an  hallu- 
cination,* but  we  see  it  in  process  of  becoming  such.  We  can 
watch  the  progressive  diminution  of  the  sensation  which 
would  contradict  it,  the  suppression  of  the  rectification  which 
wrould  pronounce  it  internal,  and  the  increase  of  the  illu- 
sion which  causes  us  to  take  the  phantasm  for  a  real  object.f 
I  know  this  state  from  my  own  experience,  and  have  many 
times  repeated  the  observation,  above  all  in  the  daytime,  when 
fatigued  and  seated  in  a  chair  ;  it  is  then  sufficient  for  me  to 
close  one  eye  with  a  handkerchief;  by  degrees  the  sight  of  the 
other  eye  becomes  vague,  and  it  closes.  By  degrees,  all  exter- 
nal sensations  are  effaced,  or  cease,  at  all  events,  to  be  remark- 
ed ;  the  internal  images,  on  the  other  hand,  feeble  and  rapid 
during  the  state  of  complete  wakefulness,  become  intense,  dis- 
tinct, colored,  steady,  and  lasting ;  there  is  a  sort  of  ecstasy, 
accompanied  by  a  feeling  of  expansion  and  of  comfort.  Warn- 
ed by  frequent  experience,  I  know  that  sleep  is  coming  on,  and 
that  I  must  not  disturb  the  rising  vision ;  I  remain  passive ; 
and,  in  a  few  minutes  it  is  complete.  Architecture,  landscapes, 
moving  figures,  pass  slowly  by,  and  sometimes  remain,  with 
incomparable  clearness  of  form  and  fulness  of  being ;  sleep 
comes  on,  and  I  know  no  more  of  the  real  world  I  am  in.  Many 
times,  like  M.  Maury,  I  have  caused  myself  to  be  gently 
roused  at  different  moments  of  this  state,  and  have  thus  been 


*  Brierre  de  Boismont,  op.  cit.  160.  Mile.  R.,  after  a  series  of  hallucinations' 
"  characterized  very  clearly  the  state  she  had  gone  through.  She  could  best  com- 
pare it,  she  said,  to  an  unpleasant  dream." — Many  sufferers  from  hallucinations 
have  said  the  same,  on  their  recovery. — The  analogy  between  dreams  and  hallu- 
cinations is  certain.  See  Maury,  ibid.  chap.  vi. 
f  Mueller,  Physiology,  tr.  Baly,  ii.  1394. 


48  OF  IMAGES.  [BOOK  II. 

able  to  mark  its  characters. — The  intense  image  which  seems 
an  external  object  is  but  a  more  forcible  continuation  of  the  fee- 
ble image  which  an  instant  before  I  recognized  as  internal ; 
some  scrap  of  a  forest,  some  house,  some  person  which  I  vaguely 
imagined  on  closing  my  eyes,  has  in  a  minute  become  present  to 
me  with  full  bodily  details,  so  as  to  change  into  a  complete  hallu- 
cination.* Then,  waking  up  on  a  hand  touching  me,  I  feel  th°. 
figure  decay,  lose  color,  and  evaporate ;  what  had  appeared 
a  substance  is  reduced  to  a  shadow.  I  have  frequently 
thus  watched  in  turn  the  filling  out  by  which  a  simple  image 
becomes  an  hallucination,  and  the  obliteration  which  turns  the 
hallucination  into  a  simple  image. — In  this  double  transition 
we  are  able  to  notice  the  differences,  and  perceive  the  condi- 
tions, of  the  two  states. 

First,  when  we  are  going  to  sleep.  As  the  image  becomes 
more  intense  so  it  becomes  more  absorbing  and  independ- 
ent. On  the  one  hand,  it  attracts  by  degrees  all  the  atten- 
tion ;  external  noises  and  contacts  become  less  and  less  sensi- 
ble ;  at  last  they  are  as  if  they  did  not  exist.  The  image,  on 
the  other  hand,  becomes  prominent  and  persistent ;  we  seem 
no  longer  actors,  but  spectators  ;  its  transformations  are  spon- 
taneous and  automatic^  When  attention  and  automatism 
are  at  their  height,  the  hallucination  is  complete,  and  it  is  pre- 
cisely by  the  loss  of  these  two  characters  that  it  is  destroyed. 
- — Next,  as  to  waking.  On  the  one  hand,  at  the  light  touch 
that  arouses  us,  a  part  of  our  attention  is  brought  back  to  the 
outer  world.  On  the  other  hand,  as  memory  returns,  reviving 
images  and  ideas  surround  with  their  train  the  special  image, 
they  come  into  conflict  with  it,  assume  ascendancy  over  it, 
depose  it  from  its  solitary  position,  restore  it  to  social  life, 
and  replace  it  in  its  habitual  dependency.  This  opposition 

*  Maury,  "  Le  Sommeil,"  3^6  edition,  pp.  448  and  453.  Many  instances  are 
cited  in  support  of  this.  "  As  soon  as  the  mind  rests  on  an  idea,  a  corresponding 

hypnogogic  hallucination  is  produced,  if  the  eye  he  closed The  state  of 

hallucination  is  nothing  more  than  an  intensity  of  the  image-idea,  owing  to  the 
internal  parts  of  the  sensorial  apparatus  having  become  more  delicate  and  more 
readily  excitable,  and  consequently  undergoing,  in  the  operation  of  conception 
a  more  vigorous  shock  than  in  the  healthy  state — a  shock,  however,  of  the  same 
naJiire  as  that  which  accompanies  though*. 

f  An  expression  of  M.  Baillarger. 


CHAP.  I.]       NATURE  AND  REDUCTION  OF  IMAGES. 


49 


and  contention  cause  the  stupefaction  of  waking,  and  what 
we  call  being  thoroughly  awake  is  but  the  re-establishment 
of  equilibrium. 

The  ordinary  image  then  is  not  a  sjmple,  but  a  double  fact. 
It  is  a  spontaneous  consecutive  sensation,  which,  by  conflict- 
ing with  another  sensation,  primitive  and  not  spontaneous, 
undergoes  lessening,  restriction,  and  correction.  It  comprises 
two  momentary  stages,  a  first  in  which  it  seems  localized 
and  external,  and  a  second  in  which  this  externality  and  sit- 
uation are  lost.  It  is  the  result  of  a  struggle  ;  ,its  tendency  to 
appear  external  is  opposed  and  overcome  by  the  stronger 
.and  contradictory  tendency  of  the  sensation  occasioned  at  the 
same  moment  by  the  action  of  the  nerve.  Under  this  ef- 
fort it  grows  weak  and  thin,  it  is  reduced  to  a  shadow  ;  we 
call  it  an  image,  phantasm,  or  appearance,  and,  however  vivid 
or  clear  it  may  be,  the  conjunction  of  this  negation  is  suffi- 
cient to  deprive  it  of  its  substance  ;  to  dislodge  it  from  its  ap- 
parent position,  and  to  distinguish  it  from  the  true  sensation. 

But  to  take  the  inverse  case  ;  it  is  allowed  that  not  only  in 
sleep  but  when  awake,  and  for  instance  in  a  state  of  ecstasy  or 
in  the  heat  of  action,  though  the  nerve  be  excited,  the  sensa- 
tion may  be  absent  or  as  if  absent,  that  is  to  say,  not  ob- 
served, annulled  by  the  presence  and  preponderance  of  some 
other  idea,  image,  or  sensation.  Such  instances  are  by  no 
means  rare.  At  the  bombardment  of  St.  Jean  d'Ulloa,  the 
Mexicans  fired  a  number  of  shot  into  a  French  vessel.  A 
sailor  called  out  "All  right!  No  harm's  done."  The  next 
minute  he  fell,  fainting  ;  a  ball  had  broken  his  arm  ;  at  the 
moment  he  did  not  feel  it.*  —  So  too  in  a  calmer  state,  we 
may  find  sensations  or  fragments  of  sensations  which  are  de- 
stroyed and  no  longer  capable  of  contradicting  the  image. 
The  image  will  then  appear  localized  and  external  ;  and,  though 
pronounced  illusory  by  surrounding  ideas,  will  continue  to  ap- 
pear localized  and  external,  since  the  sensation  which  could 
alone  deprive  it  of  this  character  is  wanting,  or  is  as  if  it  did 
not  exist.  The  hallucination  is  then  complete,  and  what  makes 
it  so  is  the  annulling  the  only  sensation  or  fragment  of 

*  This  fact  wa"s  told  me  by  an  eye-witness. 
4 


5Q  OF  IMAGES.  [BOOK  II. 

sensation  capable  of  reducing  it. — When  a  man  under  an  hal 
lucination,  with  his  eyes  open,  sees  three  feet  from  him  the 
figure  of  a  man  where  there  is  really  a  mere  wall  covered 
with  gray  paper  with  green  stripes,  the  figure  covers  a  por- 
tion of  this  wall  and  renders  it  invisible  to  him  ;  the  sensations 
which  this  portion  ought  to  excite  are  then  non-existent ;  but 
nevertheless  the  retina,  and  probably  the  optic  centres,  are 
excited  in  the  ordinary  manner  by  the  gray  and  green  stripes. 
In  other  words,  the  preponderating  image  annuls  the  portion  of 
sensation  which  would  contradict  it.  If,  as  it  often  happens, 
the  figure  moves,  the  preponderating  image,  as  it  advances 
and  covers  each  portion  of  the  wall,  is  continually  blotting  out 
and  exposing  in  turn  distinct  fragments  of  sensation.  Reason 
is  not  wanting  in  such  cases;  for  often  when  in  this  state 
the  mind  remains  sound  and  the  patient  knows  that  the  fig- 
ure is  not  real ;  it  is  the  special  reductive,  that  is  to  say,  the 
contradictory  sensation,  which  fails  in  the  conflict,  and,  in- 
stead of  depriving  the  image  of  its  externality,  becomes  itself 
effaced. 

Accidents  of  this  kind  are  frequent  when  one  of  the  senses 
has  been  greatly  fatigued.  "  It  is  well  known  that  persons  who 
are  in  the  habit  of  using  the  microscope  sometimes  find  objects 
which  they  have  been  examining  for  a  long  time  re-appear  spon- 
taneously some  hours  after  they  have  left  their  work."*  M. 
Baillarger  having  worked  some  hours  daily  for  several  days,  at 
preparing  specimens  of  brains  with  fine  gauze,  "  saw  all  at  once 

gauze  continually  covering  the  objects  in  front  of  him 

And  this  hallucination  was  repeated  for  several  days."  Here, 
it  is  evident  the  special  reductive  was  wanting ;  in  other  words, 
the  retina  having  before  it  a  green  carpet,  or  red  chair,  certain 
lines  of  green  or  of  red,  while  producing  on  it  their  ordinary 
physical  effect,  excited  only  a  sensation  amounting  to  nothing. 
For  this  reason,  a  German  physiologist,  Gruithuisen,*  who  has 
observed  his  own  hallucinations  with  great  accuracy,  affirms 
that  he  saw  floating  images  cover  the  furniture  of  the  room  he 
was  in. 

Other  cases  show  the  partial  re-establishment  of  the  correct- 


Baillarger,  "  Des  Hallucinations,"  460.     '  \  Ibid.,  333,  334. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  rj 

ive  sensation,  A  person,  mentioned  by  Sir  Walter  Scott,* 
saw  a  skeleton  at  the  foot  of  his  bed.  His  doctor,  wishing  to 
convince  him  of  his  error,  placed  himself  between  the  patient 
and  the  place  assigned  to  the  spectre.  The  patient  then  pro- 
fessed that  he  could  not  see  the  body  of  the  skeleton,  but  that 
its  skull  was  peering  over  the  doctor's  shoulder.  This  is  why 
solitude,  silence,  obscurity,  the  want  of  attention,  all  circum- 
stances, in  short,  which  suppress  or  diminish  the  corrective  sen- 
sation, facilitate  or  provoke  the  hallucination  ;  and  reciprocally, 
company,  light,  conversation,  aroused  attention,  all  circumstan- 
ces giving  rise  to,  or  augmenting,  the  corrective  sensation,  de- 
stroy or  weaken  the  hallucination. f  "  If  we  approach  a  patient 
suffering  under  hallucinations  of  hearing,  and  speak  to  him  so  as 
to  fix  his  attention,  we  can  convince  him  that  his  pretended  in- 
visible interlocutors  are  silent  while  the  conversation  lasts  .  .  ." 
A  patient  observed  by  M.  Lelut,  at  the  hospital  of  the  Bicetre," 
"  ceased  to  have  hallucinations  when  changed  into  another 
ward  and  with  different  neighbors.  But  this  suspension  last- 
ed only  a  few  days  ;  the  patient  soon  became  accustomed  to 
the  new  circumstances  in  which  he  found  himself,  and  then 
fell  again  into  false  perceptions  ....  With  one  patient  there 
must  be  very  keen  impressions,  uninterruptedly  kept  up,  to 
suspend  the  hallucinations  even  for  a  short  time.  Scarcely  is 
the  sick  man  left  to  himself,  scarcely  have  you  ceased  to  excite 
him,  when  the  phenomena  recur.  With  others,  on  the  con- 
trary, the  visit  of  the  doctor  to  the  ward  is  enough  to  cause  a 
considerable  suspension." — When  M.  Baillarger  saw  objects 
covered  with  gauze  "  it  was  principally  in  the  dark,  and  when 
my  attention  was  not  engaged.":}:  The  same  observer,  hav- 
ing taken  haschich,  could  not  get  rid  of  his  hallucinations 
while  in  the  dark,  and  was  compelled  to  light  a  candle. — Many 
patients  who  see  in  the  dark  various  frightful  figures,  dying 
persons,  corpses,  etc.,  are  freed  from  their  visions  as  soon  as 


*  "  Demonology  and  Witchcraft,"  p.  27. 

f  Baillarger,  ibid.,  440  ;  and  Brierre  de  Boismont,  op.  cit.,  388.  "  Those  nightly 
apparitions,  which  I  called  silly  illusions  by  day,  became  frightful  realities  to  me  in 
the  evening,"  p.  388. — "  It  constantly  happened  that  the  entrance  of  the  servant 
freed  her  from  the  presence  of  the  phantoms,"  p.  242. 

\  Ibid.,  328,  329,  330,  444,  445. 


52  OF  IMAGES.  [BOOK  II. 

a  light  is  brought  into  the  room,  A  lady  with  whom  this  is 
the  case  has  been  obliged  for  twenty  years  to  have  a  light  near 
her  when  asleep.  An  old  servant,  M.  G.,  "  as  soon  as  she 
closes  her  eyes,  sees  animals,  houses,  meadows,  etc.  I  have 
frequently  myself  pressed  down  her  eyelids,  and  she  described 
at  once  a  crowd  of  objects  which  appeared  to  her."  With 
some  people,  to  enter  a  dark  room  is  enough  to  produce  hal- 
lucinations. "  It  is  not  then  uncommon,"  says  Mueller,*  "  to 
find  distinct  images  of  landscapes  and  similar  objects  floating 
before  the  eyes.  I  have  been  very  subject  to  this  phenome- 
non, but  have  got  into  the  habit,  whenever  it  occurs,  of  open- 
ing my  eyes  at  once,  and  fixing  them  on  the  wall.  The  im- 
ages still  persist,  but  soon  grow  pale.  They  are  seen  which- 
ever way  the  head  is  turned."  Here  the  remedy  is  obvious  ; 
it  consists  in  arousing  a  contradictory  sensation.  The  phan- 
tom grows  pale,  and  loses  its  externality  in  proportion  as  the 
sensation  of  color  excited  by  the  wall  becomes  more  clear  and 
preponderant. — And  the  remedy  is  general ;  every  shock  that 
brings  back  the  attention  to  real  sensation ;  a  cold  bath,  a 
douche,  the  arrival  of  an  unexpected  or  important  person, 
draws  them  from  their  indistinctness  and  nullity,  re-establish- 
es them  more  or  less,  and  for  a  longer  or  shorter  time,  and 
consequently  revives  with  them  the  particular  sensation  which 
is  the  special  reductive  of  that  illusion. 

"  In  the  summer  of  i832,t  a  gentleman  in  Glasgow,  of 
dissipated  habits,  was  seized  with  cholera,  -from  which  he  re- 
covered. His  recovery  was  unattended  with  any  thing  par- 
ticular, except  the  presence  of  phantasmata — consisting  of 
human  figures  about  three  feet  high,  neatly  dressed  in  pea- 
green  jackets,  and  knee-breeches  of  the  same  color.  Being  a 
person  of  a  superior  mind,  and  knowing  the  cause  of  the  illu- 
sions, they  gave  him  no  alarm,  although  he  was  very  often 
haunted  by  them.  As  he  advanced  in  strength  the  phantoms 
appeared  less  frequently,  and  diminished  in  size,  till  at  last 
they  were  not  taller  than  his  figure.  One  night,  while  seated 
alone,  a  multitude  of  these  Lilliputian  gentlemen  made  their 
appearance  on  his  table,  and  favored  him  with  a  dance  ;  but 

*  Op.  cit.,tr.  Baly,  ii.  1394.       f  Macnish, "  Philosophy  of  Sleep,"  p.  290. 


CHAP.  I.]       NATURE  AND  REDUCTION  OF  IMAGES.  53 

being  at  the  time  otherwise  engaged,  and  in  no  mood  to  en- 
joy such  an  amusement,  he  lost  temper  at  the  unwelcome  in- 
trusion of  his  pigmy  visitors,  and  striking  his  fist  violently  on 
the  table,  he  exclaimed,  in  a  violent  passion, '  Get  about  your 
business,  you  little  impertinent  rascal !  What  the  devil  are  you 
doing  here  ?'  when  the  whole  assembly  instantly  vanished, 
and  he  was  never  troubled  with  them  more."  The  illness  was 
drawing  to  a  close,  and  his  lively  feeling  of  anger,  together 
with  the  violent  sensation  of  the  blow  on  the  table,  suddenly 
restored  their  normal  preponderance  to  the  visual  sensations 
which  the  portion  of  the  table  covered  by  the  Lilliputians 
ought  to  have  given  him,  but  had  ceased  to  give. 

Other  cases  show  with  fuller  detail  how  it  is  the  corrective 
sensation  leaves  the  sides,  and  appears  on  the  scene.  Nicolai,* 
the  bookseller  and  academician  of  Berlin,  having  suffered 
from  considerable  vexations,  and  a  periodical  blood-letting  to 
which  he  was  accustomed  having  been  omitted,  tells  his  story 
thus  : — "  On  the  24th  of  February,  1791,  having  had  a  violent 
altercation,  I  saw  on  a  sudden,  about  ten  paces  from  me,  the 

figure  of  a  corpse The  apparition  lasted  eight  minutes. 

At  four  in  the  afternoon,  the  same  figure  re-appeared 

At  six,  I  distinguished  several  figures  having  no  connexion 
with  the  first.  .  .  .  On  the  following  day,  the  figure  of  the 
corpse  disappeared  ;  it  was  replaced  by  other  figures,  sometimes 

representing  friends,  but  more  frequently  strangers. 

These  visions  were  as  clear  and  distinct  in  solitude  as  in  com- 
pany, by  day  as  by  night,  in  the  streets  as  in  my  own  house  ; 
only  they  ivere  less  frequent  when  in  strange  houses."  They 
represented  men  and  women  walking  as  if  on  business,  then 
persons  on  horseback,  dogs,  and  birds.  There  was  nothing 
particular  in  their  looks,  stature,  or  dress,  "  but  they  were  a 
little  paler  than  in  real  life"\  At  the  end  of  four  weeks, 


*  Brierre  cle  Boismont,  op.  cit.  33,  citing  from  Berliner  Monats-sclnift.  1799. 
Mai. 

f  M.  Brierre  cle  Boismont  (op.  cit.  240)  gives  an  account  of  a  person  who,  dur- 
ing an  attack  of  pneumonia,  had  hallucinations  of  this  kind,  while  preserving,  like 
Nicolai,  all  his  reason. 

"  Sometimes  these  figures  presented  themselves  suddenly,  but  more  frequently 
did  not  become  distinguishable  till  after  an  interval,  as  though  they  had  passed 


54  OF  I iMAGES.  [BOOK  II. 

their  number  increased ;  they  began  to  talk  to  one  another, 
and  sometimes  to  address  him,  usually  in  pleasing  language. 
He  distinguished  clearly  these  involuntary  hallucinations  from 
voluntary  images.  When  certain  figures  he  was  acquainted 
with  had  thus  passed  before  him,  he  determined  to  attempt 
to  reproduce  them  mentally.  "  But,"  says  he,  "  while  seeing 
distinctly  in  my  mind  two  or  three  of  them.  I  could  not  succeed 

in  making  the  internal  image  external On  the  othei 

hand,  some  time  after,  I  perceived  them  afresh  when  I  was  not 
thinking  of  them." — The  special  reductive  was  wanting  in  the 
hallucination ;  on  the  other  hand,  it  was  at  work  in  the  case 
of  ordinary  attention,  and  simply  because  the  degree  of  atten- 
tion was  ordinary.  In  the  first  case,  the  image  arising  of  its 
own  accord,  spontaneously,  without  visible  connexions  or  ante- 
cedents, and  with  personal  automatic  power,  destroyed  the 
special  reductive.  In  the  second  case,  the  image  arising  by  an 
effort  of  the  balanced  group  of  ideas  and  desires  which  we  term 
ourselves,  allowed  the  special  reductive  to  do  its  work. — After 
about  two  months,  leeches  were  applied  to  the  patient  to  make 
up  for  the  omitted  bleeding,  and  he  found  his  normal  sensations 
reappear,  not  all  at  once,  but  by  portions  and  degrees.  "  Dur- 
ing the  operation,"  says  he,  "  my  room  was  filled  with  human 
figures  of  all  kinds.  This  hallucination  lasted  uninterruptedly 
from  eleven  in  the  morning  to  half-past  four,  just  when  my  di- 
gestion was  commencing.  I  then  perceived  the  movements 
of  the  phantoms  getting  slower.  Soon  afterwards  they  began 
to  grow  pale :  at  seven  they  had  a  whitish  look,  they  moved 
very  slowly,  though  their  outlines  were  as  distinct  as  before. 
By  degrees  they  became  misty  and  appeared  to  dissolve  into  air, 
whilst  certain  portions  of  them  remained  still  visible  during  a 
considerable  time.  At  about  eight  o'clock,  the  room  was 
quite  clear  of  these  fantastic  visitors." 

When  we  are  suddenly  roused  from  sleep  in  the  midst  of 
a  vivid  dream,  we  experience  an  impression  like  this,  though 


through  a  mist  before  showing  themselves  distinctly.  Each  figure  remained  visi- 
ble five  or  six  seconds,  then  disappeared,  getting  feebler  by  degrees  till  nothing 
remained  but  an  opaque  dull  cloud,  from  the  midst  of  which  another  figure  imme- 
diately appeared." 


CHAP.  I.]       NATURE  AND   REDUCTION  OF  IMAGES. 


55 


of  far  shorter  duration.  In  such  a  case,  I  have  often  seen,  for 
a  passing  moment,  the  image  groivpale,  waste  away,  and  evap- 
orate ;  sometimes,  on  opening  the  eyes,  a  fragment  of  landscape 
or  the  skirt  of  a  dress  appears  still  to  float  over  the  fire-irons  or 
on  the  black  hearth. — So,  while  Nicolai  was  recovering,  the 
parts  of  the  wall  or  furniture  covered  by  the  phantoms  succeeded 
by  degrees  in  producing  their  normal  effect.  The  sensation 
which  they  would  naturally  excite  by  their  action  on  the  nerve, 
and  through  that  on  the  brain,  is  no  longer  paralyzed.  At 
first.,  this  sensation  recovers  a  portion  of  its  strength,  and  con- 
tends on  equal  terms  with  the  image ;  for  the  phantom,  if  still 
present,  is  misty,  and  the  furniture  or  wall  is  vaguely  apparent 
behind  it.  Soon,  a  fragment  of  the  sensation  regains  all  its 
preponderance  ;  a  leg  or  the  head  of  a  phantom  disappears 
owing  to  the  reappearance  of  the  portion  of  furniture  which 
it  hid.  Then,  the  whole  sensation  finds  itself  restored  and 
complete,  the  phantoms  have  vanished,  and  all  that  remains 
of  them  is  the  internal  image  which  enables  us  to  describe 
them. 

Here  we  see  very  clearly  the  connexion  of  the  image  and 
sensation  ;  it  is  an  antagonism,  such  as  is  met  with  between  two 
groups  of  muscles  in  the  human  frame.  In  order  that  the 
image  may  produce  its  normal  effect,  that  is  to  say,  may  be  rec- 
ognized as  internal,  it  must  undergo  the  counterpoise  of  a  sen- 
sation ;  and  if  this  counterpoise  is  absent,  it  will  appear  exter- 
nal. Similarly,  in  order  that  the  muscles  on  the  left  of  the 
face  or  tongue  may  produce  their  normal  effect,  the  corre- 
sponding muscles  on  the  right  must  be  intact.  In  the  absence 
of  this  counterpoise,  the  face  or  tongue  are  drawn  towards  the 
left.  The  paralysis  of  the  muscles  of  one  side  produces  a  de- 
formation of  the  other,  as  the  weakening  or  extinction  of  the 
reductives  of  an  image  produces  an  hallucination. 

As  a  general  rule,  normal  sensations  of  any  one  sense,  and 
usually  those  of  the  different  senses,  hold  together.  We  have 
seen  many  proofs  of  this  in  the  cases  cited.  When  the  atten- 
tion is  attracted  by  a  normal  sensation,  that  is  to  say,  when 
this  sensation  regains  its  ordinary  preponderance,  the  chances 
are  that  the  other  annulled  sensations  regain  their  ascendancy 
at  the  same  time.  The  patient  who  is  freed  at  once  from  his 


56  OF  IMAGES.  [BOOK  II. 

illusions  by  the  light  of  a  candle,  the  unfortunate  man  who 
hears  voices  which  cease  when  conversation  becomes  interest- 
ing the  lunatic  who  regains  his  senses  after  a  sudden  dash 
of  cold  water,  are  cured  for  a  longer  or  shorter  time  by  the 
more  or  less  durable  energy  restored  to  the  special  reductive. 
So,  in  facial  paralysis,  the  face  drawn  on  one  side  by  the  action 
of  the  left  muscle,  regains  its  ordinary  form  as  the  muscles  on 
the  right  gradually  regain  their  power  under  the  action  of 
electricity. 

In  other  cases  the  cure  follows  from  the  same  principles, 
but  is  obtained  by  an  inverse  process  ;  I  mean  those  in  which 
the  patient  is  haunted,  not  by  hallucinations,  that  is  to  say,  by 
images  capable  of  annulling  the  normal  sensation  which  ought 
to  counteract  them,  but  by  illusions,  that  is  to  say,  by  images 
excited  by  the  normal  sensation,  and  so  strong,  precise,  and 
absorbing  that  no  actual  sensation  from  without  could  have 
greater  power.  A  state  of  excitement  and  expectation  in  the 
subject  will  often  cause  a  sensation,  which  would  be  accompa- 
nied in  va  calm  state  by  images  of  moderate  activity,  to  com- 
municate an  extraordinary  clearness  and  force  to  the  image. 
•'  A  whole  ship's  crew  were  thrown  into  consternation  by  the 
ghost  of  the  cook,  who  had  died  a  few  days  before.  He  was 
distinctly  seen  by  them  all,  walking  on  the  water  with  a  pecu- 
liar gait  by  which  he  was  distinguished,  one  of  his  legs  being 
shorter  than  the  other.  The  cook,  so  plainly  recognized,  was 
only  a  piece  of  old  wreck."*  The  superstitious  sailors  who 
had  the  figure  of  their  shipmate  and  his  gait  fresh  in  their 
minds,  all,  without  previous  concert,  underwent  the  same 
illusion  at  the  sight  of  the  uneven  motion  of  the  wreck, 
and  their  imagination  found  in  the  sensation  a  ground  to 
build  on. 

What  was  here  effected  by  credulity  may  be  caused  by  dis- 
ease. We  see  insane  persons  who  lick  the  surface  of  a  wall 
and  imagine  themselves  to  taste  delicious  oranges,  or  who, 
when  given  ripe  fruit,  find  it  rotten  or  poisoned ;  who,  when 
they  see  one  person,  insist  on  taking  him  for  another ;  who 
see  the  furniture  of  their  room  move  about,  grow  bigger,  or 


*  Moore,  "  The  Power  of  the  Soul  over  the  Body,"  p.  170. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  57 

take  fantastic  and  frightful  forms.*  In  such  cases  it  often 
happens  that  by  suppressing  the  normal  sensation,  which  is 
the  starting  point  of  the  illusion,  we  suppress  the  illusion  it- 
self, and  the  special  reductive  is  found,  not  in  the  predomi- 
nance, but  in  the  absence  of  that  sensation.f  "  D. ,  sev- 
enty-five years  old,  of  sound  mind,  came  home  one  day,  fright- 
ened by  a  thousand  phantoms  which  were  following  him. 
Whichever  way  he  looked,  objects  ivere  transformed  into  spectres, 
representing  sometimes  huge  spiders  which  ran  at  him  to 
drink  his  blood  ;  sometimes  soldiers  with  pikes.  He  was  bled 
in  the  foot ;  the  visions  continued,  accompanied  by  obstinate 
attacks  of  sleeplessness  ;  a  bandage  was  applied  to  his  eyes  ; 
then  they  ceased,  but  returned  as  soon  as  the  bandage  was 
taken  off,  until  the  patient  kept  it  on  uninterruptedly  for  a 
night  and  part  of  a  day.  From  that  time  he  only  saw  phan- 
toms at  long  intervals,  and  after  some  days  they  disappeared 
entirely.  The  patient  has  had  no  relapse."  Here,  in  place  of 
strengthening  the  special  reductive,  the  special  excitant  was 
suppressed,  and  the  same  result  arrived  at  by  different  means. 
In  a  very  curious  observation  made  by  Dr.  Lazarus  on 
himself,  we  see  no  less  clearly  how  the  exciting  sensation, 
alternately  present  and  absent,  alternately  excites  and  sup- 
presses the  illusion.  "  I  was  on  the  Kaltbad  terrace  at  Rigi,  on 
a  very  clear  afternoon,  and  attempting  to  make  out  the  Wald- 
bruder,  a  rock  which  stands  out  from  the  midst  of  the  gigantic 
wall  of  mountains  surrounding  it,  on  whose  summits  we  see 
like  a  crown  the  glaciers  of  Titlis,  Uri-Rothsdock,  etc.  I  was 
looking  alternately  with  the  naked  eye  and  with  a  spy-glass  ; 
but  could  not  distinguish  it,  with  the  naked  eye.  For  the 
space  of  six  to  ten  minutes  I  had  gazed  steadfastly  upon  the 
mountains,  whose  color  varied  according  to  their  several 
altitudes  or  declivities  between  violet,  brown,  and  dark  green, 
and  I  had  fatigued  myself  to  no  purpose,  when  I  ceased  look- 
ing and  turned  away.  At  that  moment  I  saw  before  me  (I  can- 
not recollect  whether  my  eyes  were  shut  or  open)  the  figure 

*  Brierre  de  Boismont,  op.  cit.  777.  This  was  the  case  with  Don  Quixote  ;  the 
sensation  of  two  great  whirlwinds  of  dust  excited  in  him  the  image,  and  conse- 
quently the  sensation  of  two  armies. 

f  See  Griesinger,  op.  cit.  103,  for  different  instances. 


58  OF  IMAGES.  [BOOK  II. 

of  an  absent  friend,  like  a  corpse. — I  ought  here  to  mention 
that  I  have  been  for  years  in  the  habit  of  noting  down  in 
writing  every  group  of  representations  which  has  arisen, 
whether  dreaming  or  awake,  with  special  force,  precision,  and 
clearness,  and  has  affected  me  vividly  enough  to  induce  the 
thought  of  the  representation  as  a  presentiment.  I  ought 
further  to  mention  that  I  have  never  had  the  fortune  to  see 
one  of  such  presentiments  verified,  though  they  have  often 
been  as  sudden,  clear,  and  apparently  inexplicable,  as  one 
could  wish*.  In  addition  to  this,  I  have  acquired  the  habit, 
intelligible  enough  in  a  psychologist,  of  tracing  backwards 
from  such  incidents,  and  following  up  the  whole  series  of 
antecedent  representations.  I  have  very  often  succeeded  in 
explaining,  by  the  known  laws  of  association  of  ideas,  how 
such  presentiments  have  contrived  to  find  place  in  the  series 
of  my  thoughts  at  the  time. 

On  this  present  occasion,  I  asked  myself  at  once  how  I 
had  come  to  think  of  my  absent  friend? — In  a  few  seconds  I 
regained  the  thread  of  my  thoughts,  which  my  looking  for 
the  Waldbruder  had  interrupted,  and  readily  found  that  the 
idea  of  my  friend  had  by  a  very  simple  necessity  introduced 
itself  among  them.  My  recollecting  him  was  thus  naturally 
accounted  for. — But  in  addition  to  this,  he  had  appeared  as  a 
corpse.  How  was  this? — At  this  moment,  whether  through 
fatigue  or  in  order  to  think,  I  closed  my  eyes,  and  found  at 
once  the  whole  field  of  sight,  over  a  considerable  extent, 
covered  with  the  same  corpse-like  hue,  a  greenish-yellow  gray. 
I  thought  at  once  that  I  had  here  the  principle  of  the  desired 
explanation,  and  attempted  to  recall  to  memory  the  forms  of 
other  persons.  And,  in  fact,  these  forms  too  appeared  like 
corpses  ;  standing  or  sitting,  as  I  wished,  all  had  a  corpse- 
like  tint.  The  persons  whom  I  wished  to  see  did  not  all  ap- 
pear to  me  as  sensible  phantoms ;  and  again,  when  my  eyes 
were  open,  I  did  not  see  phantoms,  or  at  all  events  only  saw 
them  faintly,  of  no  determined  color. — I  then  inquired  how  it 
was  that  phantoms  of  persons  were  affected  by  and  colored 
like  the  visual  field  surrounding  them,  how  their  outlines  were 
traced,  and  if  their  faces  and  clothes  were  of  the  same  color. 
But  it  was  then  too  late,  or  perhaps  the  influence  of  reflection 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES. 


59 


and  examination  had  been  too  powerful.  All  grew  suddenly 
pale,  and  the  subjective  phenomenon,  which  might  have  last- 
ed some  minutes  longer,  had  disappeared. — It  is  plain  that 
here  an  inward  reminiscence,  arising  in  accordance  with  the 
laws  of  association,  had  combined  with  a  consecutive  sensation 
of  sight.  The  excessive  excitation  of  the  periphery  of  the 
optic  nerve,  I  mean  the  long-continued  preceding  sensation 
of  my  eyes  when  contemplating  the  color  of  the  mountain,  had 
indirectly  provoked 'a  subjective  and  durable  sensation,  that 
of  the  complementary  color ;  and  my  reminiscence  incorpo- 
rating itself  with  this  subjective  sensation,  became  the  corpse- 
like  phantom  I  have  described."*  This  singular  case  shows 
us  the  abnormal  effect  of  sensation.  When  it  exists,  it  in- 
creases the  force  and  clearness  of  an  ordinary  vague  represen- 
tation till  it  turns  it  into  a  sensible  phantom.  When  it  ceases, 
the  force  and  clearness  of  the  sensible  phantom  are  decreased, 
till  it  returns  to  its  ordinary  state,  that  is,  one  of  vague  rep- 
resentation. 

Thus,  in  every  process  by  which  the  exaggeration  of  images 
is  combated,  all  we  attempt  is  to  set  up  an  equilibrium,  not 
that  of  a  balance  of  which  the  two  scales  are  on  a  level,  but 
that  of  a  balance  in  which  one  scale  is  lower  than  the  other. 
In  the  normal  state  of  wakefulness,  the  first  scale  which  holds 
the  sensations  proper,  is  the  heavier ;  the  second  and  lighter 
scale  holds  images  proper.  The  two  scales  in  the  normal  state 
are,  for  the  moment,  on  a  level ;  but  the  heavier  scale  imme- 
diately weighs  down  the  other,  and  our  images  are  recognized 
as  internal.  Sometimes,  in  illness,  a  weight  passes  from  the 
first  to  the  second ;  the  second  then  weighs  down  the  first, 
and  we  have  an  hallucination  proper;  we  are  then  obliged  to 
add  new  weights,  that  is,  new  sensations,  to  the  first,  to  de- 
stroy the  preponderance.  Sometimes,  again,  a  thread  at- 
taches a  weight  of  the  second  scale  to  a  weight  of  the  first, 
the  first  scale  can  no  longer  descend,  and  we  have  an  illusion 
proper  ;  the  first  means  are  no  longer  applicable  ;  it  would  be 
idle  to  add  new  weights,  we  must  remove  from  the  first  scale 
the  weight  with  the  thread  which  keeps  the  scales  on  a  level, 


*  "  Zur  Lehre  von  den  Sinnestauschunijen,"  Berlin,  1867. 


60  OF  IMAGES.  [BOOK  H. 

in  spite  of  the  inequality  of  their  loads.  In  the  first  case,  the 
normal  state  is  re-established  by  adding ;  in  the  second,  by 
taking  off,  weights. 

V.  But  these  are  not  the  only  means  in  question ;  for,  in 
addition  to  the  weights  constituted  by  the  sensations,  there 
are  others,  lighter,  but  still  usually  sufficient  in  the  healthy 
state  to  deprive  the  image  of  its  externality ;  I  mean  recol- 
lections. These  recollections  are  themselves  images,  but  con- 
nected together  and  undergoing  a  recoil  which  gives  them  a 
situation  in  time,  by  a  mechanism  we  shall  inquire  into  here- 
after. General  judgments  acquired  by  experience  are  associa- 
ted with  them,  and  form  with  them  a  group  of  elements  con- 
nected among  themselves,  and  so  balanced,  by  their  relations 
to  one  another,  as  to  form  a  whole  of  considerable  cohesion, 
and  lending  its  entire  force  to  each  of  its  elements. — Every 
one  may  observe  in  his  own  case  the  reductive  power  of  this 
group.  A  few  days  ago,  I  had  a  very  clear  and  perfectly  con- 
nected dream,  in  which  I  committed  a  ridiculous  and  enormous 
absurdity,  too  much  so  to  describe  ;  let  us  take  something  less 
glaring,  such  as  quietly  drawing  off  one's  boots  in  company, 
and  placing  them  on  the  mantel-piece  beside  the  clock.  It 
happened  in  a  drawing-room  I  like  very  much  ;  I  saw  distinct- 
ly the  principal  guests,  their  dress,  their  attitudes,  I  spoke  to 
them,  the  scene  was  long,  and  the  impression  so  clear  that  a 
quarter  of  an  hour  after  I  could  have  described  it  with  every 
detail.  I  felt  ill  at  ease,  and  was  wondering  how  I  could  get 
out  of  my  difficulty. — Just  then  I  began  to  awake,  and  this 
state  lasted  two  or  three  minutes.  My  eyes»were  still  closed  ; 
but  probably,  through  some  feeling  of  cold  or  actual  move- 
ment, ordinary  consciousness  was  reviving,  though  feebly. 
In  the  first  place,  I  was  astonished  at  having  shown  such 
frightful  ill-breeding ;  in  other  words,  the  vague  recollection 
of  my  previous  actions  rose  up,  and  came  into  opposition  with 
my  dream  ;  this  recollection  became  more  precise,  and  brought 
on  others  ;  the  lines  of  the  past  were  reformed,  and  at  the 
same  time  and  in  the  same  degree,  the  absurdity  I  had  dream- 
ed of,  finding  no  standing-room,  disappeared  and  evaporated. 
Then  came  this  judgment,  based  on  general  ideas  : — "  It  is  a 
dream."  The  ridiculous  image,  at  once  and  definitively,  be- 


CHAP.  I.]        NATURE  AND  REDUCTION  OF  IMAGES.  6r 

came  distinct  and  severed  from  the  real  recollections,  and  en- 
tered the  region  of  pure  phantasm.  I  had  not  yet  opened 
my  eyes ;  the  sensation  of  present  objects  had  not  performed 
its  work ;  at  all  events,  it  had  only  done  so  to  the  extent  of 
reviving  ordinary  recollections  and  general  judgments  ;  these 
judgments  and  recollections,  by  the  fixedness  of  their  order 
and  the  cohesion  of  their  group,  had  effected  the  necessary 
reduction,  and  overcome  the  natural  tendency  by  which  the 
image  causes  illusion. 

In  some  cases  this  repression  is  much  slower.  M.  Baillar- 
ger  dreamed  one  night  that  a  certain  person  had  been  appoint- 
ed editor  of  a  newspaper ;  in  the  morning,  he  believed  it  to 
be  true,  and  mentioned  it  to  several  persons,  who  were  inter- 
ested to  hear  it ; — the  effect  of  the  dream  persisted  all  the  fore- 
noon, as  strongly  as  that  of  a  real  sensation ;  at  last,  about 
three  o'clock,  as  he  was  stepping  into  his  carriage,  the  illusion 
passed  off;  he  comprehended  that  he  had  been  dreaming;  so 
here  the  reductive  group  did  not  regain  its  ascendancy  for 
half  a  day. — In  this  respect,  the  detail  and  intensity  of  a  vol- 
untary image  have  sometimes  the  same  power  as  a  dream. 
We  find  many  examples  of  this  in  the  lives  of  Balzac,  Gerard 
de  Nerval,  Edgar  Poe,  and  other  great  artists.  Balzac  once, 
at  the  house  of  Mme.  Delphine  Gay,  was  describing  with  ani- 
mation a  fine  white  horse  he  intended  to  present  toSandeau  ; 
some  days  after  he  imagined  he  had  actually  given  it,  and  in- 
quired of  Sandeau  about  it ;  probably,  his  friend's  astonish- 
ment and  denial  disabused  him  of  the  notion  of  his  present. 

On  other  occasions,  the  reductive  group  is  weakened,  and 
is  not  sufficient  to  check  even  an  ordinary  image.  "An  old 
man,"  says  M.  Maury,  "  who  had  travelled  a  great  deal,  had 
also  read  many  accounts  of  travels  over  ground  where  he  had 
not  been.  The  recollections  of  his  wanderings  and  of  his 
readings  had  ended  by  becoming  completely  confused  togeth- 
er; and  all  seemed  to  occur  at  once  to  his  mind  as  he  lay  on 
his  sofa,  and  he  would  gravely  relate  things  he  had  read.  For 
example,  he  would  say  that  he  had  been  in  India  with  Tav- 
ernier,  in  the  Sandwich  Isles  with  Cook,  and  had  then  return- 
ed to  Philadelphia,  and  had  served  there  under  Lafayette. 
This  last  statement  was  true."  The  notions  of  chronology 


62  OF  IMAGES.  [BOOK  II. 

and  order  of  time  were  effaced,  and  no  longer  performed  their 
ordinary  office. 

Persons  with  lively  imaginations  are  constantly  forced  to 
make  reductions  which  this  old  man  had  ceased  to  make  ;  the 
general  order  of  their  recollections,  fortified  by  the  addition 
of  some  new  observation,  is  generally  sufficient  for  this.  But 
when  an  image  has  acquired  extraordinary  intensity,  and 
annuls  the  particular  sensation  which  is  its  special  reductive, 
though  the  order  of  recollections  may  exist  and  conclusions 
be  come  to,  we  have,  nevertheless,  an  hallucination ;  in  fact, 
we  may  know  that  we  are  under  an  hallucination,  but  still  the 
image  appears  external ;  our  other  sensations  and  images  still 
form  a  balance  group,  but  this  reductive  not  being  the  special 
one,  is  insufficient. — "  Dr.  Gregory  had  gone  to  the  north 
country  by  sea,  to  visit  a  lady,  a  near  relation,  in  whom  he 
felt  deeply  interested,  and  who  was  in  an  advanced  state  of 
consumption.  In  returning  from  the  visit,  he  had  taken  a 
moderate  dose  of  laudanum,  with  the  view  of  preventing  sea- 
sickness, and  was  lying  on  a  couch  in  the  cabin,  when  the 
figure  of  the  lady  appeared  before  him  in  so  distinct  a  manner 
that  her  actual  presence  could  not  have  been  more  vivid.  He 
was  quite  awake,  and  fully  sensible  that  it  was  a  phantasm 
produced  by  the  opiate,  along  with  his  intense  mental  feeling, 
but  he  was  unable  by  any  effort  to  banish  the  vision."*  In 
fact,  the  sensation  which  ought  to  have  been  produced  in  him 
by  the  gray  wall  of  the  cabin  was  annulled  as  regarded  the 
whole  surface  which  the  phantom  seemed  to  cover ;  and  it  is 
very  clear  that  reasoning  has  not  the  force  of  a  sensation. — 
Many  circumstances,  organic  or  moral,  the  action  of  haschich,f 
of  datura,  of  opium,  the  coming  on  of  apoplexy,  different  in- 
flammatory diseases,  different  cerebral  alterations,  in  short,  a 
number  of  causes,  more  or  less  remote  or  near,  are  capable  of 
thus  strengthening  an  image  or  series  of  images  so  as  to  annul 
the  special  sensation  which  should  repress  it,  and  thus  bring 
on  hallucination. — But  if  in  all  these  cases  the  illusion,  circum- 


*  Abercrombie,  "  Inquiry  concerning  the  Intellectual  Powers,"  p.  359. 
f  Brierre  de  Boismont,  ibid.,  200.     Accounts  given  by  several  persons  who  had 
taken  haschich.     Ibid.,  374. 


CHAP.  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  63 

scribed  by  secondary  reductives,  is  at  last  destroyed  by  the 
special  one,  we  meet  with  a  still  greater  number  in  which  this 
is  not  the  case.  Very  frequently,  patients,  having  admitted 
for  a  length' of  time  that  their  phantoms  were  only  phantoms, 
have  ended  by  believing  them  to  be  real,  and  equally  real 
with  the  persons  and  objects  surrounding  them,  and  this  too 
with  so  absolute  a  conviction  that  no  experience  of  their  own 
or  evidence  of  others  can  cure  them  of  their  error.  In  such 
cases  the  second  class  of  reductives  are  annulled,  as  well  as 
the  special  one  ;  the  preponderating  image,  having  paralyzed 
the  contradictory  sensation,  extends  its  dominion  over  the  con- 
tradictory group  of  other  normal  images,  and  excites  delirious 
ideas  and  unreasonable  impulses.  The  person  under  hallu- 
cination becomes  a  madman  ;  the  loss  of  local  equilibrium  has 
gradually  brought  on  an  increasing  loss  of  general  equilibrium, 
as  the  paralysis  of  the  muscles  on  the  right,  after  causing  a 
deformation  and  shrinking  of  the  face  towards  the  left,  may 
affect  by  sympathy  the  adjoining  functions,  and  produce  gen- 
eral disease  throughout  the  body. 

Examples  of  this  are  numerous ;  I  have  chosen  one,  re- 
ported by  Dr.  Lhomme,  which  shows  in  detail  the  several 
stages  of  this  spontaneous  transformation,  and  throws  great 
light  on  the  mechanism  of  the  mind. 

In  March,  1862,  the  gendarme  S.  was  on  duty  at  an  exe- 
cution. He  was  on  guard  with  the  prisoner  during  part  of 
the  night,  assisted  at  the  toilette,  and  was  a  few  feet  from  the  scaf- 
fold when  the  execution  took  place.  When  the  head  fell,  he  saw 

the  executioner  take  it  up  to  put  it  in  the  basket He  says 

that  this  made  a  deep  impression  on  him  ;  he  had  been  seized 
with  a  nervous  trembling  which  he  could  not  control,  at  the  mo- 
ment he  saw  the  prisoner  brought  up  with  his  outer  clothes  re- 
moved and  neck  bare  ;  and  long  after  the  execution,  the  fig- 
ure of  the  bleeding  head  which  he  had  seen  thrown  into  the  bas- 
ket was  constantly  before  him. 

Some  time  after,  talking  with  the  quartermaster,  he  said 
that  he  had  no  great  opinion  of  Protestants.  "  He  told  me  I 
was  wrong ;  that  there  were  many  very  good  people  among 
them,  and  even  some  persons  of  high  rank,  and  mentioned,  as 
an  instance,  the  Minister  of  War.  I  kept  thinking  of  this  con- 


64  °F  IMAGES.  [BOOK  II. 

versation,  and  it  came  into  my  head  that  the  quartermaster 
would  probably  report  me  to  the  Minister  of  War.  Some  days 
afterwards  I  dreamed  that  I  was  actually  condemned  to  dcatJi 
by  the  Minister's  order,  without  having  had  a  trial.  I  thought 
in  my  dream  that  I  was  bound  with  straps  and  was  being  rolled 
like  a  barrel  towards  the  guillotine.  This  dream  impressed  me 
vividly.  I  told  it  to  a  comrade,  who  laughed  at  me,  but  it  often 
recurred  to  my  mind !  " 

On  the  1st  of  August,  going  from  Sancerre  to  Sancergues, 
he  got  drunk,  arrived  too  late,  and  found  the  barracks  closed. 
Next  day  the  quartermaster  told  him  that  he  should  report 
him  to  the  lieutenant  for  being  late. — The  2d  of  August  he 
was  "  out  of  spirits,  but  not  ill."  The  3d  of  August,  he  says, 
"  I  did  not  feel  all  right,  though  I  had  slept  well ;  /  kept  think- 
ing of  my  dream When  I  went  on  duty  as  sentry,  I 

thought  every  one  was  staring  at  me,  and  that  I  heard  my  com- 
rades and  other  persons  whispering  that  I  was  going  to  be 
guillotined'' 

That  evening  he  went  to  bed  at  eleven,  having  cleaned 
his  accoutrements  for  next  day's  drill.  "  I  had  perhaps  been 
in  bed  twenty  minutes,  and  had  not  fallen  asleep,  when  I 
heard  a  noise  in  the  clock  over  the  mantel-piece,  and  then  a 
voice  came  from  it,  and  said  to  me,  "  You  must  die,  you  must 
die.  Your  head  will  be  cut  off  in  two  days.  We  must  have  your 
head,  we  must  have  your  head  !  "  He  started  up  and  looked  in 
the  clock,  but  there  was  nothing  to  be  seen,  so  thinking  it  a 
joke  of  his  comrades,  he  went  to  bed  again.  The  voice  began 
again,  and  he  was  looking  about  during  part  of  the  night. 
About  four  in  the  morning  he  rose,  without  having  slept,  and 
went  to  drill,  but  said  nothing  of  the  voice  he  had  heard,  as 
he  "  still  thought  that  his  comrades  had  been  playing  him  a 
trick."  Coming  back  he  was  tired,  but  could  not  eat,  and 
cleaned  his  accoutrements ;  he  felt  no  inclination  to  sleep,  and 
did  not  go  to  bed  till  one  in  the  morning.  He  was  scarcely 
in  bed  when  he  heard  the  same  voice  and  same  words  proceed- 
ing from  the  clock.  "  Then  I  rose  and  walked  up  and  down, 
very  certain  that  they  would  execute  me  next  morning,  and 
that  that  was  why  the  lieutenant  had  remained  at  Sancergues." 

He  rose  early.     "  The  quartermaster  was  surprised  to  see 


CHAP.  I.]       NATURE  AND   REDUCTION  OF  IMAGES.  65 

me  ready  so  soon,  and  said  something  in  a  low  tone  to  my  com- 
rades. /  thought  I  heard,  '  See  that  your  carbines  are  loaded ; 
watch  him  that  he  does  not  escape ! ' ' 

On  this  he  found  his  horse,  and  set  off  at  a  gallop  without 
knowing  where  he  was  going.  At  last  he  came  to  a  wood, 
got  off,  and  hid  himself  in  a  thicket,  and  loaded  his  carbine  to 
defend  himself;  then  he  determined  to  kill  himself,  and  took 
off  his  boots  that  he  might  draw  the  trigger  with  his  foot,  but 
first  knelt  to  say  a  prayer.  "  I  was  soon  interrupted  by  a  fig- 
ure with  a  huge  beard,  who  disappeared  as  soon  as  I  took  aim 
at  him ;  and  three  times  running  I  was  stopped  by  the  same 
apparition  or  by  figures  of  Punch,  which  disappeared  as  I  was 
going  to  fire.  I  saw  also  girls  with  hooped  petticoats,  dancing 
in  the  trees  above  my  head." 

The  other  gendarmes  came  up ;  he  threatened  to  fire  on 
them,  attempted  to  take  off  his  white  breeches  to  hide  himself 
better;  then,  hearing  them  return,  he  fired  on  the  foremost 
of  them,  and  attempted  to  escape,  but  was  taken.  "  I  was 
quite  convinced  that  they  were  going  to  take  me  to  execu- 
tion, and  called  out '  Murder !'  I  even  thought  more  than  once 
that  I  saw  a  gendarme  draw  his  knife  from  his  pocket  to  stab 
me,  and  my  cries  increased."  He  was  bound,  and  a  guard  put 
over  him  and  did  not  sleep  all  night.  *'  I  continually  heard 
female  voices  saying,  'Poor  fellow !  how  unfortunate !  He 
must  be  guillotined  in  two  Jwurs*  and  his  head  sent  to  Paris  by 
six  o  clock.  The  quartermaster  has  the  basket  for  it!  The 
whole  day  and  night  of  the  6th  I  had  the  same  ideas,  and 
could  not  sleep  for  a  moment  or  take  any  kind  of  nourishment. 
It  was  not  till  the  /th  that  I  was  able,  during  the  daytime,  to 
throw  myself  on  my  bed  and  sleep  for  a  short  time.  When  I 
woke  I  found  my  head  completely  clear,  though  I  recollected 
perfectly  all  that  had  taken  place.  I  expressed  my  sorrow  to 
my  comrades  for  what  had  passed,  and  asked  at  once  after  the 
one  I  had  wounded."  From  that  time  the  hallucinations 
ceased :  the  patient's  reason  is  unaffected ;  he  was  calm  and 
quiet  during  his  stay  in  an  asylum,  and  is  replaced  in  the 
brigade  of  Gendarmerie,  and  has  regularly  performed  his  duty 
since. 

Few  examples  are  most  instructive  than  this ;  we  follow 


66  OF  IMAGES.  [BOOK  II. 

the  hallucination  from  its  first  rise  to  its  completed  state  and 
its  cure.  The  mental  abscess  begins  with  a  terrible  image, 
combined  with  extreme  emotion. — The  image  constantly  re- 
viving besets  the  mind. — It  attaches  itself  to  the  idea  of  self, 
and  S imagines  a  case  in  which  he  may  well  be  in  person- 
al danger. — This  connexion  becomes  defined,  and  in  a  dream 
he  sees  himself  led  to  the  guillotine.  The  dream  returns  to 
his  mind  during  the  day.  After  he  has  committed  a  fault  it 
recurs  with  greater  force. — The  mental  words  by  which  he  ex- 
presses it  to  himself  become  a  whispering  of  his  comrades,  and 
then  a  voice  in  the  clock. — The  voice  returns,  and  his  convic- 
tion grows  firmer. — Unconnected  hallucinations  of  sight,  then 
of  the  touch,  follow. — For  thirty  hours  the  voices  continue, 
and  the  hallucination  of  the  ear  is  at  its  height. — Then  he  be- 
comes suddenly  freed  from  them,  as  if  the  mental  abscess 
having  ripened,  had  broken  of  itself.* 

VI.  From  these  examples  we  can  form  a  notion  of  our  in- 
tellectual machinery.  We  must  lay  aside  the  words  reason, 
intelligence,  will,  personal  power,  and  even  self,  as  we  lay  aside 
the  words  vital  force,  medicative  virtue,  vegetative  soul ;  they 
are  literary  metaphors,  capable  at  the  most  of  convenient  use 
by  way  of  summary  or  abbreviation,  to  express  general  states 
and  combined  effects.  All  that  observation  detects  physi- 
ologically in  the  living  being  are  cells  of  different  kinds,  ca- 
pable of  spontaneous  development,  and  modified  in  the  direc- 
tion of  this  development  by  the  concurrence  or  antagonism  of 
their  neighbors.  All  that  observation  detects  psychologically 
in  the  thinking  being  are,  in  addition  to  sensations,  images  of 
different  kinds,  primitive  or  consecutive,  endued  with  certain 
tendencies,  and  modified  in  their  development  by  the  concur- 
rence or  antagonism  of  other  simultaneous  or  contiguous  im- 
ages. Just  as  the  living  body  is  a  polypus  of  mutually  de- 
pendent cells,  so  the  Active  mind  is  a  polypus  of  mutually  de- 
pendent sensations  and  images,  and  in  the  one  case  as  in  the 
other,  unity  is  nothing  more  than  a  harmony  and  an  effect. 
Every  image  is  possessed  of  an  automatic  force,  and  tends 
spontaneously  to  a  particular  state  ;  to  hallucination,  false 


*  "  Annales  Medico-Psychologiques,"  46  Serie,  ii.  238. 


CHAP,  I.]      NATURE  AND  REDUCTION  OF  IMAGES.  67 

recollection,  and  the  other  illusions  of  madness.  But  it  is  ar- 
rested in  its  progress  by  the  contradiction  of  a  sensation,  of 
another  image,  or  group  of  images.  The  mutual  arrest,  the 
reciprocal  clash,  the  repression,  produce  by  their  combined 
effect  an  equilibrium ;  and  the  effect  we  have  just  seen  pro- 
duced by  the  special  corrective  sensation,  by  the  connexion 
of  our  recollections,  by  the  order  of  our  general  judgments, 
is  but  an  instance  of  the  constant  re-arrangement  and  inces- 
sant limitation  which  innumerable  incompatibilities  and  con- 
flicts are  incessantly  bringing  about  among  our  images  and 
ideas.  This  equilibrium  is  the  state  of  reasonable  wakeful- 
ness.  As  soon  as  it  is  at  an  end  by  the  hypertrophy  or  atro- 
phy of  an  element,  we  are  mad,  wholly  or  partially.  When 
it  lasts  over  a  certain  time,  the  fatigue  is  too  great,  and  we 
sleep  ;  our  images  are  no  longer  reduced  and  guided  by  antag- 
onistic sensations  coming  from  the  outer  world,  by  the  re- 
pressive effect  of  combined  recollections,  by  the  dominion 
of  well-connected  judgments ;  so  they  then  acquire  their 
full  development,  turn  into  hallucinations,  arrange  themselves 
spontaneously  according  to  new  tendencies,  and  sleep,  though 
crowded  with  intense  dreams,  is  a  rest,  since,  suppressing  a 
constraint,  it  brings  on  a  state  of  relaxation. 

But  in  the  mean  while  the  reader  has  been  able  to  ascertain 
the  nature  of  the  image.  For  this  we  must  remain  at  the 
point  at  which  we  have  provisionally  placed  ourselves.  We 
do  not  yet  enter  upon  physiology,  but  confine  ourselves  to 
pure  psychology.  We  do  not  talk  of  nerves,  spinal  marrow, 
or  brain.  We  leave  aside  the  unknown  excitation  which  the 
external  extremity  of  the  nerve  undergoes  by  contact  with  an 
external  object,  and  which  transmits  itself  to  the  spinal  mar- 
row, passes  thence  to  the  surface  of  the  brain,  spreads  among 
its  circumvolutions,  becomes  persistent  in  the  nervous  centres, 
and  is,  later  on,  renewed  there.  We  do  not  examine  the  link 
connecting  the  sensation  with  the  image.  We  observe  man, 
not  with  the  scalpel  and  microscope,  but  with  that  internal 
view  we  call  consciousness,  and  we  compare  directly  the  image 
and  the  sensation. — In  this  limited  field,  and  in  this  precise 
sense,  we  have  just  seen  that  the  image,  with  different  physi- 
cal stimulants,  and  a  special  reductive,  is  of  the  same  nature 


68  OF  IMAGES.  [BOOK  II. 

as  the  sensation.  It  is  the  sensation  itself,  but  consecutive  or 
reviving;  and  from  whatever  point  we  consider  it,  we  find  it 
coincide  with  the  sensation. — It  furnishes  the  same  combina- 
tions of  derived  and  superior  ideas  ;  the  chess-player  who  plays 
blindfolded,  the  painter  who  copies  an  absent  model,  the  mu- 
sician who  hears  a  score  when  he  looks  over  the  sheet  of  music, 
form  the  same  judgments,  go  through  the  same  reasonings, 
and  experience  the  same  emotions,  as  if  the  chess-board,  the 
model,  the  symphony,  were  actually  experienced  by  their 
senses. — It  provokes  the  same  instinctive  movements  and  the 
same  associated  sensations :  the  man  who  has  a  disgusting  medi- 
cine put  before  him,  who  is  about  to  undergo  a  surgical  opera- 
tion, who  recalls  a  melancholy  or  terrible  accident,  shudders, 
sweats,  or  is  sick,  in  presence  of  the  image  alone,  as  he  would  if 
the  sensation  were  itself  present. — Though  generally  fragmen- 
tary, fugitive,  and  weak,  it  arrives  in  many  cases,  in  the  ex- 
treme concentration  of  excessive  attention,  in  violent  and 
sudden  emotions,  at  a  state  bordering  closely  on  the  corre- 
sponding sensation,  and  attains  the  fulness  of  detail,  the  clear- 
ness, energy,  and  persistence  of  the  sensation. — Finally,  taken 
alone  and  freed  from  the  reduction  of  its  special  corrective, 
it  acquires  apparent  externality,  the  want  of  which,  even  at 
its  maximum  of  intensity,  usually  distinguishes  it  from  the 
sensation ;  it  acquires  this  for  an  imperceptible  moment  in 
the  majority  of  cases  ;  for  some  seconds  or  minutes  in  certain 
well-authenticated  instances ;  for  several  hours,  days,  or  weeks 
in  the  states  of  half  sleep,  complete  sleep,  ecstasy,  hypnotism, 
somnambulism,  hallucination ;  in  the  disorders  produced  by 
opium  or  haschich,  in  various  cerebral  or  mental  maladies  ;  and 
acquires  it  with  or  without  lesion,  or  with  either  partial  or  total 
lesion,  of  the  normal  equilibrium  which  subsists  between  other 
ideas  and  images. — We  may  define  it,  then,  as  a  repetition  or 
revival  of  the  sensation,  while  at  the  same  time  we  distinguish 
it  from  the  sensation ;  first,  by  its  origin,  since  it  has  the  sen- 
sation as  its  antecedent,  while  the  sensation  is  preceded  by 
an  excitation  of  the  nerve ;  and  again,  by  its  association  with 
an  antagonist,  since  it  has  several  reductives,  among  others, 
the  special  corrective  sensation,  while  the  sensation  itself 
has  no  reductive. 


CHAP.  I.]        NATURE  AND  REDUCTION  OF  IMAGES.  69 

Arrived  at  this  we  understand  its  nature  :  in  reviving  the 
sensation,  it  replaces  it ;  it  is  its  substitute ;  that  is  to  say,  a 
thing  differing  from  it  in  certain  respects,  like  it  in  others, 
but  so  that  both  differences  and  resemblances  have  their  ad- 
vantages. What  these  advantages  are  we  shall  see  later  on. 
Images  of  a  certain  kind  constitute  recollections ;  that  is  to 
say,  knowledge  of  past  events.  Images  associated  with  the 
sensations  of  the  different  senses,  especially  with  those  of  sight 
*md  touch,  constitute  acquired  perceptions ;  that  is  to  say,  all 
such  parts  of  our  knowledge  of  external  individual  objects  as 
extend  beyond  actual  crude  sensation.  Images  of  a  certain 
kind,  and  associated  in  a  certain  way,  constitute  previsions ;  that 
is  to  say,  knowledge  of  future  events. — Just  as  the  knowledge 
of  general  qualities  is  only  possible  by  the  substitution  of 
signs  for  perceptions  and  images,  so  knowledge,  whether  of 
events  past  or  to  come,  or  of  the  grouped  properties  which 
make  up  every  individual  external  object,  is  only  possible  by 
the  substitution  of  images  for  sensations. — Nature  employs,  in 
the  two  cases,  the  same  process  to  arrive  at  the  same  effect ; 
psychology  here  repeats  physiology.  As  we  see  iir  the  his- 
tory of  respiration  or  of  locomotion  a  physiological  element 
become,  by  a  slight  modification,  the  instrument  of  a  more 
complicated  function,  then,  by  a  second  additional  modifica- 
tion, execute  a  still  superior  function ;  so  in  the  history  of  in- 
telligence, we  see  a  psychological  element  give  rise,  by  a  small 
modification,  to  very  extended  operations,  then,  by  a  second, 
added  modification,  accomplish  operations  so  complex,  so  deli- 
cate, and  so  numerous,  that  they  seem  destined  to  remain 
forever  beyond  our  grasp. 


OF  IMAGES.  [BOOK  II. 


CHAPTER  II. 

LAWS  OF  THE  REVIVAL  AND  OBLITERATION  OF  IMAGES.      * 

I.  WHEN  we  see  or  touch  an  object,  when  we  hear  a 
sound,  when  we  experience  a  sensation  of  taste,  of  smell,  of 
cold,  of  pain,  in  short,  any  sensation  whatever,  we  usually  re- 
tain the  image  during  a  second  or  two,  unless  some  other  sen- 
sation, image  or  idea,  comes  in  the  way,  and  suppresses  in- 
stantly this  prolongation  and  echo.  But  in  many  cases,  and 
above  all  when  the  sensation  has  been  a  prominent  and  im- 
portant one,  the  image  revives  of  itself  after  a  longer  or  shorter 
period  of  suppression.  This  spontaneous  revival  is  its  fun- 
damental property,  and  may  be  effected  after  long  periods 
have  elapsed.  Many  of  us  have  recolleetions  which  go  back 
twenty,  thirty,  forty  years,  or  more.  I  know  a  person,  born  in 
a  little  provincial  town,  who  can  relate  with  the  utmost  exac- 
titude all  the  circumstances  of  a  visit  of  the  Empress  Marie- 
Louise  in  1812,  can  describe  her  dress,  the  dresses  of  the  la- 
dies and  young  girls  appointed  to  receive  her,  can  hear  men- 
tally the  sound  of  her  voice,  see  her  gestures,  her  face,  the  at- 
titudes of  the  persons  appointed  to  present  her  with  an  address, 
and  many  other  things. — What  renders  these  revivals  still 
more  remarkable  is  that  they  frequently  occur  without  the 
image  having  reappeared  during  the  whole  interval.  On  re- 
turning, after  many  years'  absence,  to  one's  father's  house,  or 
to  one's  native  village,  numbers  of  forgotten  objects  and  facts 
unexpectedly  reappear.  The  mind,  suddenly  thronged  by 
their  stirring  crowd,  resembles  a  box  of  dried  rotifera,  which 
have  lain  inert  some  ten  years,  but  when  sprinkled  with  water, 
at  once  revive  and  twist  about.  We  mount  the  dark  staircase, 
we  know  where  to  find  the  handle  of  the  door,  we  imagine 
ourselves  seated  at  table  in  cur  accustomed  place,  we  see  the 


CHAP.  II.]  REVIVAL  AND  OBLITERATION  OF  IMAGES.  jl 

water-bottle  on  the  right,  and  the  salt-cellar  on  the  left,  we 
seem  to  taste  the  flavor  of  some  Sunday  dish.  We  look  up  at 
the  wall  and  are  surprised  not  to  find  there  some  old  engrav- 
ing we  had  stared  at  as  children.  We  see  the  gesture  and 
stoop  of  some  former  guest,  the  square  body  and  long  folds  of 
a  blue  dress ;  we  almost  hear  the  tones  of  voices  which  have 
long  been  still.  We  come  to  the  well,  and  recall  the  vague 
terror  with  which  as  children,  mounting  on  tiptoe,  we  looked 
on  the  obscure  depth  and  the  trembling  reflection  of  the  cold 
water  at  what  seemed  to  us  an  infinite  distance  below. 

•Some  people  unconsciously  preserve  certain  reviving'shreds 
of  long-distant  impressions. — "  There  often  recurred  to  my 
mind,"  says  M.  Maury,  "  without  my  knowing  why,  three 
proper  names,  each  accompanied  by  the  name  of  .a  town  in 
France.  One  day  I  came  across  an  old  newspaper  and  com- 
menced to  read  it  for  want  of  any  thing  better  to  do.  Among 
the  advertisements  I  saw  one  of  a  depot  of  mineral  waters, 
with  the  names  of  the  druggists  who  sold  them  in  the  princi- 
pal towns  of  France.  There  I  found  my  three  unknown  names 
with  those  of  the  three  towns  with  which  they  were  con- 
nected in  my  mind.  All  was  explained  ;  my  memory,  which 
is  excellent  for  words,  had  preserved  a  recollection  of  these 
associated  names,  on  which  my  eyes  must  have  rested  while 
I  was  looking  (  as  had  happened  about  two  months  previously) 
for  the  address  of  a  depot  of  mineral  waters.  But  the  circum- 
stance had  gone  out  of  my  mind  without  the  recollection 
being  wholly  effaced.  Now,  certainly,  I  could  not  have  paid 
much  attention  in  so  rapid  a  glance." 

Illness  sometimes  causes  a  revival  of  such  images  as  this  of 
names,  which  seemed,  not  merely  torpid,  but  hopelessly  ex- 
tinct. "  A  girl  was  seized  with  a  dangerous  fever,  and,  in  the 
delirious  paroxysm  accompaying  it,  was  observed  to  speak 
in  a  strange  language  which,  for  some  time,  no  one  could  un- 
derstand. At  last  it  was  ascertained  to  be  Welsh — a  tongue 
of  which  she  was  wholly  ignorant  at  the  time  she  was  taken 
ill,  and  of  which  she  could  not:  speak  a  single  syllable  after  her 
recovery.  For  some  time  the  circumstance  was,  unaccount- 
able, till,  on  inquiry,  it  was  found  that  she  was  a  native  of 
Wales,  and  had  been  familiar  with  the  language  of  that  coun- 


72  OF  IMAGES.  [BOOK  II. 

try  in  her  childhood,  but  had  wholly  forgotten  it  afterwards."* 
— Again  ;  some  fugitive  impressions,  not  observed  at  the 
time,  may  rise  anew  with  strange  power  and  automatic  exact- 
ness. Many  medical  writers  have  noticed  the  storyf  of  a 
young  woman  of  five-and-twenty  who  could  neither  read  nor 
write,  who,  during  an  illness,  repeated  long  passages  of  Latin, 
Greek,  and  Rabbinical  Hebrew,  but  on  recovery,  spoke  noth- 
ing but  her  own  language.  During  her  delirium,  several  of 
these  fragments  were  taken  down  in  writing  from  her  own 
mouth.  After  inquiry,  it  was  found  that  she  had  lived,  when 
nine  years  old,  with  her  uncle,  a  clergyman  of  considerable 
learning,  who  was  in  the  habit  of  walking  of  an  afternoon  in  a 
passage  adjoining  the  kitchen,  and  there  reciting  favorite 
passages  of  Rabbinical  Hebrew  and  Greek.  On  referring  to 
his  books,  there  were  found,  word  for  word,  many  of  the  pas- 
sages repeated  by  the  sick  girl.  The  noise  and  articulation  of 
his  voice  had  remained  fixed  in  her  ears.  She  had  heard 
them  as  she  repeated  them  without  understanding  them.^: 
Haschich,  the  death-agony,§  great  and  sudden  emotion,  some- 
times cause  revivals,  equally  minute,  of  sensations  as  little 
observed  and  still  farther  distant. — We  can  assign,  then,  no 
limits  to  these  revivals,  and  are  compelled  to  ascribe  to  every 


*  Macnish,  "  Philosophy  of  Sleep,"  p.  55,  n.  ;  and  see  two  analogous  facts  cited 
by  Azam,  "  Annales  Medico-Psychologiques,"  3e  Serie.vi.  443. 

\  Coleridge,  "  Biographia  Literaria,"  vol.  i.  p.  117. 

\  "A  man  of  ordinary  ability,  servant  of  a  Spanish  ambassador,  had  frequently 
to  be  present  during  important  conferences,  but  did  not  appear  to  have  recollect- 
ed any  thing  of  what  had  passed.  He  was  seized  with  brain  fever,  and  in  his  de- 
lirium repeated  with  considerable  order  many  discussions  he  had  heard  on  the  polit- 
ical interests  of  different  powers,  so  much  so  that  the  ambassador,  who  had  con- 
sidered him  only  as  a  faithful  servant,  came  to  hear  him,  and  thought  of  promoting 
him  to  be  his  secretary  ;  but  the  affection  of  the  brain  passed  off,  and  when  the 
patient  recovered,  this  memory  had  departed." — (Grimaud  de  Caux,  cited  by  Duval 
Jouve,  "Traite  de  Logique,"  159.) 

§  "  I  was  once  told  by  a  near  relative  of  mine,  that  having  in  her  childhood 
fallen  into  a  river,  and  being  on  the  very  verge  of  death,  ....  she  saw  in  a  moment 
her  whole  life,  arrayed  before  her  as  in  a  mirror,  not  successively,  but  simulta- 
neously ;  and  she  had  a  faculty  developed  as  suddenly  for  comprehending  the 
whole  and  every  part." — De  Quincey,  "  Confessions,  etc."  p.  258. — De  Quincey 
and  other  opium-eaters  have  observed  in  themselves  this  faculty  of  living  mentally, 
during  a  dream  of  a  few  minutes,  a  life  of  many  years,  and  even  of  many  centuries. 


CHAI-.  II.]  REVIVAL  AND  OBLITERATION  OF  IMAGES.  73 

sensation,  however  rapid,  unimportant  or  obliterated  it  may 
have  been,  an  indefinite  power  of  revival,  without  mutilation 
or  loss,  even  after  an  enormous  distance  of  time ;  just  as  a 
vibration  of  ether,  which,  starting  from  the  sun,  transmits  itself 
through  millions  of  leagues  till  it  reaches  our  optical  apparatus, 
with  its  special  spectrum  and  its  proper  rays,  the  same  at  its 
starting-point  and  at  its  place  of  arrival,  intact,  and  capable, 
by  its  exact  conservation,  of  manifestating  on  the  instrument 
receiving  it  the  nature  of  the  fire  from  which  it  is  emitted. 

II.  If,  however,  we  compare  different  sensations,  images, 
or  ideas,  we  find  that  their  aptitudes  for  revival  are  not  equal. 
A  large  number  of  them  are  obliterated,  and  never  reappear 
through  life  ;  for  instance,  I  drove  through  Paris  a  day  or  two 
ago,  and  though  I  saw  plainly  some  sixty  or  eighty  new  faces, 
I  cannot  now  recall  any  one  of  them  ;  some  extraordinary  cir- 
cumstance, a  fit  of  delirium,  or  the  excitement  of  haschich 
would  be  necessary  to  give  them  a  chance  of  revival.  On  the 
other  hand,  there  are  sensations  with  a  force  of  revival  which, 
nothing  destroys  or  decreases.  Though,  as  a  rule,  time  weak- 
ens and  impairs  our  strongest  sensations,  these  reappear  entire 
and  intense,  without  having  lost  a  particle  of  their  detail,  or 
any  degree  of  their  force.  M.  Brierre  de  Boismont,*  having 
suffered  when  a  child  from  a  disease  of  the  scalp,  asserts  that 
"  after  fifty-five  years  have  elapsed  he  can  still  feel  his  hair 
pulled  out  under  the  treatment  of  the  skull-cap!' — For  my 
own  part,  after  thirty  years,  I  remember  feature  for  feature 
the  appearance  of  the  theatre  to  which  I  was  taken  for  the 
first  time.  From  the  third  row  of  boxes,  the  body  of  the 
theatre  appeared  to  me  an  immense  well,  red  and  flaming, 
swarming  with  heads  ;  below,  on  the  right,  on  a  narrow  floor, 
two  men  and  a  woman  entered,  went  out,  and  re-entered, 
made  gestures,  and  seemed  to  me  like  lively  dwarfs  :  to  my 
great  surprise,  one  of  these  dwarfs  fell  on  his  knees,  kissed 
the  lady's  hand,  then  hid  behind  a  screen  ;  the  other,  who  was 
coming  in,  seemed  angry,  and  raised  his  arm.  I  was  then 
seven,  I  could  understand  nothing  of  what  was  going  on  ;  but 
the  well  of  crimson  velvet  was  so  crowded,  gilded,  and  bright, 


*  Brierre  de  Boismont,  op.  cit.  376. 


74  OF  IMAGES.  [BOOK  II. 

that  after  a  quarter  of  an  hour  I  was,  as  it  were,  intoxicated, 
and  fell  asleep. 

Every  one  of  us  may  find  similar  recollections  in  his  mem- 
ory, and  may  distinguish  in  them  a  common  character.  The 
primitive  impression  has  been  accompanied  by  an  extraor- 
dinary degree  of  attention,  either  as  being  horrible  or  delight- 
ful, or  as  being  new,  surprising,  and  out  of  proportion  to  the 
ordinary  run  of  our  life  ;  this  it  is  we  express  by  saying  that 
we  have  been  strongly  impressed ;  that  we  were  absorbed, 
that  we  could  not  think  of  any  thing  else  ;  that  our  other  sen- 
sations were  effaced ;  that  we  were  pursued  all  the  next  day 
by  the  resulting  image ;  that  it  beset  us,  that  we  could  not 
drive  it  away ;  that  all  distractions  were  feeble  beside  it.  It 
is  by  force  of  this  disproportion  that  impressions  of  childhood 
are  so  persistent ;  the  mind  being  quite  fresh,  ordinary  objects 
and  events  are  surprising.  At  present,  after  seeing  so  many 
large  halls  and  full  theatres,  it  is  impossible  for  me,  when  I 
enter  one,  to  feel  swallowed  up,  engulfed,  and  as  it  were,  lost 
in  a  huge  dazzling  well.  The  medical  man  of  sixty,  who  has 
experienced  much  suffering,  both  personally  and  in  imagina- 
tion, would  be  less  upset  now  by  a  surgical  operation  than  when 
he  was  a  child. 

Whatever  may  be  the  kind  of  attention,  voluntary  or  in- 
voluntary, it  always  acts  alike  ;  the  image  of  an  object  or  event 
is  capable  of  revival,  and  of  complete  revival,  in  proportion  to 
the  degree  of  attention  with  which  we  have  considered  the 
object  or  event.  We  put  this  rule  in  practice  at  every  mo- 
ment in  ordinary  life.  If  we  are  applying  ourselves  to  a  book, 
or  are  in  lively  conversation,  while  an  air  is  being  sung  in  the 
adjoining  room,  we  do  not  retain  it ;  we  know  vaguely  that 
there  is  singing  going  on,  and  that  is  all.  We  then  stop  our 
reading  or  conversation,  we  lay  aside  all  internal  pre-occupa- 
tions  and  external  sensations  which  our  mind  or  the  outer 
world  can  throw  in  our  way ;  we  close  our  eyes,  we  cause  a 
silence  within  and  about  us,  and,  if  the  air  is  repeated,  we 
listen.  We  say  then  that  we  have  listened  with  all  our  ears, 
that  we  have  applied  our  whole  minds.  If  the  air  is  a  fine 
one,  and  has  touched  us  deeply,  we  add  that  we  have  been 
transported,  uplifted,  ravished,  that  we  have  forgotten  the 


CHAP.  II.]  REVIVAL  AND  OBLITERATION  OF  IMAGES.  75 

world  and  ourselves ;  that  for  some  minutes  our  soul  was  dead 
to  all  but  sounds. — And,  in  fact,  there  are  numerous  examples 
in  which,  under  the  empire  of  a  ruling  idea,  all  other  sensations, 
however  violent,  are  annihilated ;  such,  for  instance,  is  the 
story  of  Pascal,  who  one  night  solved  the  problem  of  the  cy- 
cloid, to  distract  his  mind  from  violent  pain  in  the  teeth ; 
that  again  of  Archimedes,  who,  in  tracing  geometrical  diagrams, 
was  unconscious  of  the  storrning  of  Syracuse.  Such  also  are 
the  frequent  and  well-proved  instances  of  soldiers,  who,  in  the 
excitement  of  action,  do  not  notice  their  wounds,  and  those 
of  ecstatics,  of  somnambulists,  and  of  hypnotized  persons. — 
These  authentic  instances,  and  these  metaphors  of  language, 
all  bring  to  light  the  same  fact,  that  is  to  say,  the  more  or 
less  complete  and  universal  cancelling  of  all  sensations,  images, 
or  ideas  in  favor  of  a  single  one ;  this  last  one  being  persist- 
ent and  absorbing,  produced  and  prolonged  with  an  energy 
usually  dispersed  over  several.  In  other  words,  we  are  set  up 
for  a  time  in  a  fixed  and  determinate  form  ;  the  contrary  solici- 
tations, the  different  tendencies  which  result  in  another  state, 
the  other  images,  ideas,  and  sensations  which  are  striving  for 
production,  remain  in  an  incipient  and  abortive  state.  The 
given  form  is  incompatible  with  them,  and  checks  their  devel- 
opment. What  happens  in  us  is  just  what  takes  place  in  a 
solution  when  a  crystal  is  formed ;  the  particles  which  had  no 
affinity  for  any  special  structure  now  place  themselves  in  a 
mass  in  fixed  order ;  their  unstable  equilibrium  is  followed 
by  a  stable  equilibrium  whose  rigid  and  precise  direction  resists 
the  different  agitations  of  the  air  and  the  fluid. 

This  exclusive  momentary  ascendancy  of  one  of  our  states 
of  mind  explains  the  greater  durability  of  its  aptitude  for  re- 
vival and  for  more  complete  revival.  As  the  sensation  revives 
in  the  image,  the  image  reappears  with  a  force  proportioned 
to  that  of  the  sensation.  What  we  meet  with  in  the  first 
state  is  also  to  be  met  with  in  the  second,  since  the  second  is 
but  a  revival  of  the  first.  So,  in  the  struggle  for  life,*  in 


*  "  Struggle  for  life"  (Darwin).  We  shall  see  later  on  the  development  of  this 
doctrine.  The  theory  of  the  great  English  naturalist  is  nowhere  more  precisely 
applicable  than  in  psychology. 


76  OF  IMAGES,  [BOOK  II. 

which  all  our  images  are  constantly  engaged,  the  one  furnish- 
ed at  the  outset  with  most  force,  retains  in  each  conflict,  by 
the  very  law  of  repetition  which  gives  it  being,  the  capacity 
of  treading  down  its  adversaries  ;  this  is  why  it  revives,  inces- 
santly at  first,  then  frequently,  until  at  last  the  laws  of  pro- 
gressive decay,  and  the  continual  accession  of  new  impressions, 
take  away  its  preponderance,  and  its  competitors,  finding  a 
clear  field,  are  able  to  develope  in  their  turn. 

A  second  cause  of  prolonged  revivals  is  repetition  itself. 
Every  one  knows  that  to  learn  a  thing  we  must  not  only  con- 
sider it  attentively,  but  consider  it  repeatedly.  We  say  as  to 
this  in  ordinary  language,  that  an  impression  many  times  re- 
newed is  imprinted  more  deeply  and  exactly  on  the  memory. 
This  is  how  we  contrive  to  retain  a  language,  airs  of  music, 
passages  of  verse  or  prose,  the  technical  terms  and  propositions 
of  a  science,  and  still  more  so  the  ordinary  facts  by  which  our 
conduct  is  regulated.  When,  from  the  form  and  color  of  a 
currant  jelly,  we  think  of  its  taste,  or  when  tasting  it  with  our 
eyes  shut,  we  imagine  its  red  tint  and  the  brilliancy  of  a 
quivering  slice,  the  images  in  our  mind  are  brightened  by  rep- 
etition. Whenever  we  eat,  or  drink,  or  walk,  or  avail  our- 
selves of  any  of  our  senses,  or  commence  or  continue  any 
action  whatever,  the  same  thing  happens.  Every  man  and 
every  animal  thus  possesses  at  every  moment  of  life  a  certain 
stock  of  clear  and  easily  reviving  images,  which  had  their 
source  in  the  past  in  a  confluence  of  numerous  experiences, 
and  are  now  fed  by  a  flow  of  renewed  experiences.  When  I 
want  to  go  from  the  Tuileries  to  the  Pantheon,  or  from  my 
study  to  the  dining-room,  I  foresee  at  every  turn  the  color- 
ed forms  which  will  present  themselves  to  my  sight ;  it  is 
otherwise  in  the  case  of  a  house  where  I  have  spent  two  hours, 
or  of  a  town  where  I  have  stayed  three  days ;  after  ten  years 
have  elapsed  the  images  will  be  vague,  full  of  blanks,  some- 
times they  will  not  exist,  and  I  shall  have  to  seek  my  way  or 
shall  lose  myself. — This  new  property  of  images  is  also  de- 
rived from  the  first.  As  every  sensation  tends  to  revive  in  its 
image,  the  sensation  twice  repeated  will  leave  after  it  a  double 
tendency,  that  is,  provided  the  attention  be  as  great  the  second 
time  as  the  first ;  usually  this  is  not  the  case,  for  the  novelty 


CHAP.  II.]    REVIVAL  AND  OBLITERATION  OF  IMAGES. 


77 


diminishing,  the  interest  diminishes  ;  but  if  other  circumstan- 
ces renew  the  interest,  or  if  the  will  renovates  the  attention, 
the  incessantly  increasing  tendency  will  incessantly  increase 
the  chances  of  the  resurrection  and  integrity  of  the  image. 

III.  These  are  but  the  general  conditions  of  revival ;  we 
obtain  them  by  comparing  an  image  taken  at  any  point  of  its 
existence  with  another  image  at  any  point  of  its  existence. 
We  have  npw  to  compare  two  adjoining  moments  in  the  same 
mind,  and  to  determine  the  more  special  conditions  which  ex- 
cite at  any  time  the  birth  of  one  image  rather  than  of  anoth- 
er.— For  this,  let  us  consider,  not  only  isolated  sensations,  but 
also  series  of  sensations.  These  have  a  similar  tendency  to*" 
revival,  and  the  law  which  is  applicable  to  tile  elements  is  also 
applicable  to  the  compounds.  On  some  days,  without  wishing 
it,  we  pass  over  in  our  mind  some  portion  o£our  life,  such  as 
a  day's  travel,  some  evening  at  the  opera,  some  interesting 
conversation.  We  feel  ourselves  brought  back  in  a  fixed 
manner  to  a  former  state ;  the  ideas  which  attempt  to  throw 
themselves  in  the  way  are  unwelcome ;  they  are  driven  out, 
or  rest  on  the  threshold  ;  if,  at  the  first  moment,  some  gap  was 
found  in  our  recollection,  it  usually  ends  by  supplying  itself; 
a  forgotten  detail  rises  unexpectedly. — I  recollect  at  this  mo- 
ment an  evening  spent  at  Laveno  on  the  Lago  Maggiore,  and 
as  I  dwell  on  it,  I  see  my  dinner  at  the  inn,  the  coarse  white 
cloth,  the  pretty  startled  servant ;  then,  a  moment  after,  the 
path  winding  among  thyme  and  lavender,  the  grayish-blue 
lake  under  its  moist  cloud  of  vapor,  the  patches  of  light,  the 
glittering  tracks,  the  sprinkled  silver  scales  which  a  stray  sun- 
beam had  embroidered  in  places  on  its  level  sheet,  the  im- 
perceptible rustling  made  by  the  little  waves  on  the  shore, 
and  the  bells  of  the  cows  tinkling  here  and  there  in  the  silence. 
All  the  prominent  points  in  the  group  of  sensations  I  then  had, 
reappear  in  turn  or  together. — If  now,  taking  one  of  these 
points,  I  inquire  how  it  emerged,  I  find  that  it  was  when  it  had 
already  commenced  to  emerge.  For  instance,  when  I  have  re- 
called the  winding  lines  of  the  path,  and  imagine  myself  turn- 
ing to  the  left,  I  recall  the  slate-colored  lake  and  its  embroid- 
ery of  shining  spangles,  and  above,  the  peaked  mountains  de- 
scending in  green  slopes  to  the  water ;  I  find  that  the  extreme 


78  OF  IMAGES.  [BOOK  II 

edge  of  the  bank  borders  the  lake,  the  uniform  surface  is 
striped  with  brilliant  fringes,  and  on  the  other  side,  the  water 
rejoins  the  meadows  and  rising  slopes ;  thus,  the  extremity 
of  one  image  coincides  with  the  commencement  of  the  next, 
and  so  the  latter  begins  to  revive  as  the  first  disappears.  In 
the  same  way,  the  murmur  of  the  tiny  waves  and  the  tinkling 
of  the  bells  revert  to  me  when  my  visual  images  are  those  of 
the  lake  and  the  bank ;  a  commencement  of  imaginary  sound 
accompanied  the  imaginary  colored  forms  ;  it  disengages  it- 
self, and  we  feel  it  reproduced  with  all  its  shades,  and  up  to 
its  end.  The  partial  revival  results  in  a  total  revival. — This 
is  so  true  that  if,  upsetting  the  natural  tendency  of  the  images 
to  revert  in  the  order  of  the  sensations,  I  attempt  to  repro- 
duce the  series  inversely,  I  am  able  to  call  up  the  former  sen- 
sations from  the  latter  ones  as  soon  as  I  can  hit  on  the  point 
of  contact  in  which  they  touch  the  ones  they  have  followed. 
In  fact,  if  I  now  trace  backwards  up  to  my  arrival  at  the  inn, 
I  see  again  the  old  oak  some  twenty  paces  from  the  house, 
two  or  three  trunks  of  felled  trees,  and  a  dozen  vagabonds 
strolling  about  or  sleeping  in  the  warmth  of  the  evening  sun ; 
thus  by  calling  up  the  point  of  contact,  that  is  to  say,  the  com- 
mencement of  the  image,  I  supply  to  the  image  the  means  of 
reviving  as  a  whole. — In  fact,  to  speak  correctly,  there  is  no 
isolated  and  separate  sensation.  A  sensation  is  a  state  which 
begins  as  a  continuation  of  preceding  ones,  and  ends  by  los- 
ing itself  in  those  following  it ;  it  is  by  an  arbitrary  severing, 
and  for  the  convenience  of  language,  that  we  set  it  apart  as 
we  do ;  its  beginning  is  the  end  of  another,  and  its  ending  the 
beginning  of  another.  By  force  of  the  general  law  which  con- 
nects it  to  the  image,  its  image  has  the  same  properties  as 
itself;  therefore  this  image  itself  arouses  at  its  earlier  extrem- 
ity the  ending  of  another  image,  and  at  its  later  extremity 
the  commencement  of  another  image,  in  such  a  way  that 
the  precedents  and  consequents  of  the  sensation  have  also 
indirectly  their  echo  in  the  image  of  the  sensation. 

Further  than  this,  as  different  sensations  are  often  similar 
in  part,  as  soon  as  the  image  of  one  among  them  appears,  the 
images  of  the  others  partially  appear.  When  just  now  I  was 
describing  the  sparkling  streaks  which  the  sun  made  on  the 


CHAP.  II.]    REVIVAL  AND  OBLITERATION  OF  IMAGES. 


79 


water,  I  compared  them  to  embroidery, 'to  fringes,  and  to 
spangles  of  silver ;  the  portion  common  to  these  four  sensa- 
tions, present  in  the  first,  successively  revived  the  three  others. 
Here  again,  the  partial  revival  has  resulted  in  a  total  revival. — 
We  have  often  a  difficulty  in  observing  this  partial  revival.  It 
seems  to  us,  at  the  first  glance,  that  such  an  idea  has  arisen 
involuntarily  and  by  chance  ;  we  cannot  see  how  it  is  connect- 
ed with  the  foregoing  one.  This  results  from  the  idea  which 
seems  to  have  immediately  preceded  it,  not  having  really  done 
so ;  there  were  intermediate  stages  between  them,  which 
habit,  inattention,  or  the  speed  of  the  operation,  have  prevent- 
ed our  observing ;  these  intermediate  stages  have  served  for 
an  invisible  transition,  and  it  has  been  through  them  that  the 
law  of  Contiguity,  or  the  law  of  Similarity,  has  applied. 
Hobbes,  one  of  the  first  originators  of  this  theory,  relates* 
how,  in  the  midst  of  a  conversation  on  the  English  civil  war, 
some  one  suddenly  asked  what  was  the  value,  under  Tiberius, 
of  the  Roman  penny;  an  abrupt  question  seemingly  uncon- 
nected with  what  had  gone  before.  There  was,  however,  a 
connexion,  and  with  a  little  thought  he  recovered  it.  The 
English  civil  war,  under  Charles  the  First, — Charles  the  First 
delivered  up  by  the  Scotch  for  2OO,ooo/.  sterling, — Jesus 
Christ  similarly  betrayed  for  thirty  pence  under  Tiberius. 
These  were  the  links  of  the  chain  which  led  the  speaker  to  his 
remarkable  inquiry.f — We  see  now  how  the  celebrated  laws 
governing  the  association  of  images,  and  consequently  that 
of  ideas,:}:  are  reduced  to  a  more  simple  law.  What  excites 


*  "Leviathan,"  part  i.  ch.  3,  vol.  iii.  p.  12  (Ed.  Molesworth). 

f  "  An  instance  of  this  occurs  to  me  with  which  I  was  recently  struck.  Think- 
ing of  Ben  Lomond,  this  thought  was  immediately  followed  by  the  thought  of  the 
Prussian  system  of  education.  Now,  conceivable  connexion  between  these  two 
ideas  in  themselves,  there  was  none.  A  little  reflection,  however,  explained  the 
anomaly.  On  my  last  visit  to  the  mountain,  I  had  met  upon  its  summit  a  German 
gentleman,  and  though  I  had  no  consciousness  of  the  intermediate  and  unwakened 
links  between  Ben  Lomond  and  the  Prussian  schools,  they  were  undoubtedly 
these, — the  German, — Germany, — Prussia, — and,  these  media  being  admitted,  the 
connexion  between  the  extremes  was  manifest. — Sir  W.  Hamilton,  "  Lectures,'* 
etc.,  i.  p.  353. 

\  See  Bain,  "  Senses  and  Intellect."  He  derives  all  the  operations  of  the  intel- 
lect from  these  two  laws.  See  also  Mervoyer,  "Etude  sur  1' Association  des  Idees' 
(1864). 


80  OF  IMAGES.  [BOOK  II. 

at  any  moment  a  particular  image  rather  than  any  other,  is  a 
commencement  of  the  revival ;  and  this  revival  has  already 
commenced,  either  by  similitude,  from  the  anterior  image  or 
sensation  containing  a  portion  of  the  reviving  image ;  or  by 
contiguity,  from  the  anterior  image  becoming  confused  at  its 
end  with  the  commencement  of  the  reviving  image.  Given 
any  image  at  any  particular  moment,  we  can  always  explain 
its  actual  presence  by  its  commencement  of  revival  in  the 
preceding  image  or  sensation ;  and  its  clearness,  force,  apti- 
tude for  revival  and  other  intrinsic  qualities,  by  the  amount 
of  attention  it  has  received,  and  number  of  revivals  it  has 
undergone,  either  in  itself  or  in  the  corresponding  sensation. 
All,  it  will  be  observed,  comprised  in  our  fundamental  law, 
which  discovers  the  tendency  to  revival  in  the  sensation  and 
in  its  image,  and  which,  therefore,  assures  to  the  commenced 
image,  to  the  image  accompanied  by  attention,  and  to  the 
image  strengthened  by  repetitions,  a  preponderance  which 
results  in  its  revival. 

IV.  The  same  laws  explain  the  opposite  event ;  by  sup- 
pressing or  weakening  the  conditions  which  increase  an  image's 
chance  of  revival  and  preponderance,  we  suppress  its  chances 
of  ascendancy  and  revival. — In  the  first  place,  all  that  lessens 
the  attention  lessens  these  chances.  Every  minute  we  expe- 
rience twenty  sensations,  of  heat,  cold,  pressure,  contact,  mus- 
cular contraction  ;  slight  sensations  like  these  are  being  in- 
cessantly produced  in  all  parts  of  our  bodies ;  in  addition  to 
this,  sounds,  murmurings,  and  hummings,  are  constantly  go- 
ing on  in  our  ears ;  a  number  of  little  sensations  of  smell  and 
taste  arise  in  pur  noses  and  throats  ;  but  we  are  otherwise  en- 
gaged— we  are  thinking,  meditating,  talking,  reading — and 
during  all  this  time  we  neglect  other  things.  As  regards  other 
sensations,  we  are  as  if  asleep  or  in  a  dream ;  the  ascendancy 
of  some  dominant  image  or  sensation  keeps  them  in  a  nascent 
state.  If,  at  the  end  of  a  minute,  we  attempt  to  recall  them 
by  memory,  they  do  not  revive  ;  they  are  like  seeds  sown  by 
the  handful,  but  which  have  not  grown  ;  some  single  one, 
more  lucky,  has  monopolized  to  itself  all  the  room  and  nutri- 
ment the  earth  affords. — It  does  not  necessarily  follow  that 
these  sensations,  destined  to  obliteration,  are  feeble  ones  : 


CHAP.  II.]   REVIVAL  AND  OBLITERATION  OF  IMAGES.  gl 

they  may  be  powerful  ones  :  it  is  sufficient  that  they  should 
be  weaker  than  the  privileged  one.  A  musket-shot,  the  flash 
of  a  cannon,  a  painful  wound,  frequently  escape  attention  in 
the  heat  of  battle,  and,  not  having  been  observed,  cannot  re- 
vive ;  a  soldier  suddenly  finds  he  is  bleeding,  without  being 
able  to  recollect  the  blow  he  has  received. — In  nine  cases  out 
of  ten,  and  perhaps  in  ninety-nine  out  of  a  hundred,  the  sensa- 
tion loses  in  this  manner  its  power  of  revival,  because  there 
cannot  be  attention  without  distraction,  and  the  predominance 
acquired  vby  one  impression  is  a  predominance  taken  from  the 
others.  Here  again,  things  are,  as  it  were,  in  a  balance  ;  one 
scale  can  only  rise  by  lowering  the  other,  and  the  lowering  or 
elevation  of  the  one  is  in  proportion  to  the  elevation  or  lower- 
ing of  the  other. 

On  the  other  hand,  the  want  of  repetition  also  diminish- 
es the  chances  of  revival.  Every  one  knows  that  we  forget 
many  of  the  words  of  a  language  when  we  have  given  up  read- 
ing or  speaking  it  for  many  years.  So  it  is  with  an  air  we  no 
longer  sing,  with  a  piece  of  verse  we  no  longer  recite,  with  a 
neighborhood  we  have  been  long  absent  from.  Breaks  occur 
in  the  train  of  recollections,  and  go  on  increasing  like  the 
holes  in  an  old  garment. — We  have  no  difficulty  in  seeing  how 
continuous  and  vast  these  destructions  must  be  ;  every  day  we 
lose  some  of  our  recollections,  three-fourths  of  those  of  the 
preceding  day,  then  others  among  those  surviving  from  the 
previous  month,  so  that  before  long  a  whole  month,  or  even 
year,  is  only  represented  in  our  memory  by  certain  prominent 
images,  like  those  few  peaks  still  appearing  in  a  submerged 
continent,  destined,  at  least  the  most  of  them,  themselves  to 
disappear,  since  the  gradual  obliteration  is  owing  to  a  contin- 
uous flood,  invading  one  by  one  the  untouched  crags,  and  spar- 
ing nothing  but  a  few  rocks  uplifted  by  some  extraordinary 
circumstances  to  a  height  no  wave  can  reach.  In  fact,  very 
few  of  our  sensations,  even  of  those  accompanied  by  attention, 
are  often  repeated.  Six  months  ago'I  was  talking  to  such  a 
person  ;  after  I  left  him,  and  even  on  the  following  day,  I  could 
have  described  his  appearance  and  dress,  have  repeated  the 
principal  topics  of  conversation  ;  but  since  then  I  have  not  re- 
newed in  experience  or  repeated  in  memory  the  images  which 
6 


82  OF  IMAGES.  [BOOK  II. 

then  revived  in  me,  intact  and  connectedly.  They  are  obliter- 
ated, and  now,  when  by  chance  I  find  some  fragment  of  the 
distant  scene,  and  stop  to  call  up  the  rest,  my  efforts  are  vain. 
— So  it  happens  with  nearly  all  the  portions  of  our  experience: 
the  impression  received  has  been  a  solitary  one  ;  in  a  thousand 
such,  there  is  at  most  one  which  is  twice  repeated  ;  in  a  thou- 
sand of  the  repeated  ones,  there  is  scarcely  one  whick  is  repeat- 
ed twenty  times.  Some  few  only — those  of  permanent  objects 
surrounding  us — of  some  twenty  or  thirty  persons,  pieces  of 
furniture,  monuments,  streets,  landscapes,  derive  from  constant 
repetition  a  multiplied  aptitude  for  revival.  With  the  others, 
the  aptitude  is  too  weak;  when  a  fragment  of  distant  experi- 
ence, with  which  they  were  formerly  connected,  reappears,  they 
do  not  reappear  with  it ;  the  tendency  which  formerly  called 
them  up  is  vanquished  by  other  tendencies  formed  in  the  mean 
while ;  and  the  recent  past  blocks  up  the  way  of  the  earlier 
past. 

Finally,  on  the  other  hand,  images  grow  dull  by  repetition, 
as  bodies  are  worn  away  by  friction.  If  we  see  a  person  eight 
or  ten  times,  the  outline  of  his  form  and  expression  of  his  face 
become  at  last  much  less  clear  in  our  mind  than  on  the  day 
after  we  have  first  seen  him.  So  it  is  with  a  monument,  a 
street,  a  landscape,  when  seen  many  times  at  different  hours 
of  the  day,  at  evening,  in  the  morning  ;  on  a  dull  day,  in  rain, 
under  a  bright  sun,  if  we  compare  them  with  the  same  monu- 
ment, landscape,  or  street,  watched  for  three  minutes,  and  then 
replaced  by  some  entirely  different  object.  The  impression, 
so  precise  at  first,  becomes  less  so  the  second  time.  When  I 
imagine  the  monument,  I  find  indeed  the  outline,  which  has 
remained  constant  all  the  time,  but  the  distribution  of  light 
and  shade,  the  changing  nature  of  the  tones,  the  look  of  the 
gray  or  blackened  pavement,  the  band  of  sky  above — grayish 
and  misty  in  the  one  case,  dark  and  tarnished  in  the  other ; 
sometimes  a  bright  white,  sometimes  a  dark  purple — in  short, 
all  the  diversities  which  at  different  moments  have  connected 
themselves  with  its  permanent  form,  are  mutually  annulled. 
And  so,  when  I  think  of  a  person  I  know,  my  memory  wavers 
between  twenty  different  expressions,  smiling,  serious,  unhap- 
py, the  face  bent  on  one  side  or  the  other.  These  different 


CHAP.  II.]    REVIVAL  AND  OBLITERATION  OF  IMAGES.  83 

expressions  form  obstacles  of  each  other ;  my  recollection  is 
far  clearer  when  I  have  only  seen  him  for  a  minute — when,  for 
instance,  I  have  looked  at  his  photograph  or  picture. 

In  fact,  when  the  image  of  the  form  we  have  perceived 
tends  to  revive,  it  draws  with  it  the  images  of  its  several  ac- 
companiments. But  these  accompaniments  being  different 
cannot  revive  together ;  the  features  of  the  same  face  cannot 
be  at  once  smiling  and  severe  ;  the  fagade  of  the  same  palace 
cannot  be  at  once  of  an  intense  black,  as  when  the  sun  is  set- 
ting behind  it,  and  of  a  rosy  brightness,  as  when  it  is  rising  in 
front  of  it.  Therefore,  if  these  mutually  excluding  accompa- 
niments have  an  equal  tendency  to  revive,  neither  one  nor  the 
other  will  do  so,  and  we  shall  feel  ourselves  drawn  in  different 
directions  by  contrary  tendencies  which  come  to  nothing ;  the 
images  will  remain  in  an  inchoate  state,  and  will  make  up  what 
we  call  in  ordinary  language  an  impression.  This  impression 
may  be  strong  without  ceasing  to  be  vague  ;  beneath  the  in- 
complete image  a  dull  agitation  is  going  on,  and  as  it  were,  a 
swarm  of  feeble  impulses'which  usually  sum  themselves  up  in 
an  expressive  gesture,  a  metaphor,  a  visible  summary.  Such 
is  our  usual  state  as  regards  things  we  have  many  times  expe- 
rienced ;  a  vague  image,  corresponding  to  a  portion  of  our 
different  experiences,  a  heap  of  contrary  tendencies  of  nearly 
equal  force,  corresponding  to  their  different  circumstances,  a 
clear  notation,  denoting  and  concentrating  the  whole  in  an 
idea. 

This  law  of  obliteration  is  of  considerable  extent,  for  it  is 
applicable  not  only  to  different  appearances  of  the  same  object, 
but  also  to  different  objects  of  the  same  class  ;  and  all  the  ob- 
jects in  nature  may  be  grouped  in  classes.  A  man  who  has 
passed  through  an  alley  of  poplars,  and  wishes  to  figure  to 
himself  a  poplar,  or  who,  after  seeing  a  large  farm-yard,  wishes 
to  figure  to  himself  a  hen,  experiences  a  difficulty.  His  dif- 
ferent recollections  encroach  upon  each  other ;  the  differences 
which  distinguished  the  two  hundred  poplars  or  the  hundred 
and  fifty  hens  are  mutually  obliterated  ;  he  will  preserve  a  more 
precise  image  if  he  has  only  seen  a  single  poplar  standing  in 
a  meadow  or  a  single  hen  roosting  in  ashed. — All  our  images 
undergo  a  similar  blunting ;  let  the  reader  attempt  to  imagine 


84  OF  IMAGES.  [BOOK  II. 

a  rabbit,  a  carp,  a  pike,  a  bull,  a  rose,  a  tulip,  a  birch  tree 
or  any  other  object  belonging  to  a  numerous  class  and  of 
which  he  has  seen  many  individuals,  and  on  the  other  hand, 
an  elephant,  a  hippopotamus,  a  magnolia,  an  American  aloe, 
or  any  other  object  of  a  small  class,  and  of  which  he  has  only 
met  with  one  or  two  specimens ;  in  the  first  case  the  image  is 
vague  and  all  its  surroundings  have  disappeared ;  in  the  sec- 
ond it  is  precise,  and  one  is  able  to  point  out  the  spot  in  the 
Jardin  des  Plantes,  the  Parisian  Conservatory,  the  Italian  villa, 
where  the  object  was  seen. — The  multiplication  of  experience 
is  then  a  cause  of  obliteration,  and  images,  by  annulling  one 
another,  thus  fall  into  the  state  of  dull  tendencies  hindered 
by  their  contrariety  and  equality  from  assuming  an  ascend- 
ancy. 

V.  Thus  we  arrive  at  a  general  conception  of  the  history 
of  images,  and,  consequently,  of  ideas  in  a  human  mind. 
Every  sensation,  weak  or  strong,  every  experience,  great  or 
small,  tends  to  revive  by  means  of  an  internal  image  which 
repeats  it,  and  is  itself  capable  of  repeating,  even  after  long 
pauses,  and  this  indefinitely.  But  as  sensations  are  numer- 
ous, and  are  at  every  moment  replaced  by  others,  without 
truce  or  termination,  up  to  the  end  of  life,  there  is  a  conflict 
of  preponderance  between  these  images,  and,  though  all  tend 
to  revive,  those  alone  do  so,  which  have  the  prerogatives  re- 
quired by  the  laws  of  revival ;  all  the  others  remain  incom- 
plete or  null,  according  to  the  laws  of  obliteration. — By  force 
of  this  double  law,  groups  of  efficacious  aptitudes  are  constant- 
ly becoming  inefficacious,  and  images  are  falling  from  the  state 
of  actual  to  that  of  possible  existence.  Thus,  human  memory 
is  like  a  vast  reservoir,  into  which  daily  experience  is  continu- 
ally pouring  different  streams  of  tepid  waters ;  these  waters 
being  lighter  than  the  others  rest  on  the  surface  and  cover 
them ;  then  growing  cold  in  their  turn,  they  descend  to  the 
bottom  by  portions  and  degrees,  and  it  is  the  last  flow  that 
constitutes  the  new  surface.  Sometimes  a  particular  stream, 
from  being  swollen  or  having  a  higher  fall,  warms  ancient  in- 
ert layers  below,  and  then  they  remount  to  the  light  ;  the 
chance  of  the  flow  and  the  laws  of  equilibrium  have  warmed  a 
certain  layer  so  as  to  place  it  above  the  rest.  The  shape  of 


CHAP  II.]    REVIVAL  AND  OBLITERATION  OF  IMAGES.  $c 

the  reservoir,  the  accidents  of  temperature,  the  various  quali- 
ties of  the  water,  sometimes  even  shocks  of  earthquake,  all 
bear  part  in  this  ;  and  many  authentic  instances  show  us  deep 
layers  uplifted  suddenly  and  entire  to  the  surface,  sometimes 
superficial  layers  plunged  suddenly  and  entire  below. 

In  fact,  images  have,  as  we  shall  see  later  on,  certain  states 
of  brain  as  conditions  of  their  being ;  hence,  we  understand 
how  an  injury,  a  rush  of  blood,  a  deterioration  of  blood,  any 
change  of  the  cerebral  substance,  may  hinder  or  promote  the 
arising  of  certain  groups  of  images.  "  I  descended  on  the 
same  day,"  says  Sir  Henry  Holland,*  "  two  very  deep  mines 
in  the  Hartz  mountains,  remaining  some  hours  underground 
in  each.  While  in  the  second  mine,  and  exhausted  both  from 
fatigue  and  inanition,  I  felt  the  utter  impossibility  of  talking 
longer  with  the  German  inspector  who  accompanied  me. 
Every  German  word  and  phrase  deserted  my  recollection, 
and  it  was  not  until  I  had  taken  food  and  wine,  and  been 
some  time  at  rest,  that  I  regained  them." — Similar  mischances 
are  not  uncommon  after  brain  fevers  or  great  losses  of  blood. 
A  lady,  says  Winslow,f  after  large  uterine  haemorrhage,  "  had 
forgotten  where  she  lived,  who  her  husband  was,  how  long 
she  had  been  ill,  the  names  of  her  children,  and  even  her  own 
name.  She  was  unable  to  give  any  thing  its  real  name,  and 
in  attempting  to  do  so,  made  the  most  singular  mistakes. 
She  had  been  accustomed,  before  her  illness  to  speak  French 
instead  of  English.  But  afterwards  she  seemed  to  have  lost 
all  knowledge  of  French  ;  for,  when  her  husband  addressed  her 
in  that  language,  she  did  not  appear  to  understand  what  he  said 
the  least  in  the  world,  though  she  could  converse  in  English 
without  difficulty,"  After  seven  or  eight  weeks  these  blanks 
in  her  memory  began  to  be  restored  ;  and  after  some  months 
they  were  entirely  filled  up.  So  a  gentleman,  mentioned  by 
Abercrombie,  "  after  a  blow  on  the  head,  lost  his  knowledge 
of  Greek,  and  did  not  appear  to  have  lost  any  thing 


*  "  Chapters  on  Mental  Physiology,"  p.  167,  n.  cited  by  Winslow,  "  Obscure 
Diseases,"  etc.  p.  252. 

f  Winslow,  ibid.,  p.  344. 

J  "  Inquiry  into  the  Intellectual  Powers,"  p.  152. 


86  OF  IMAGES.  [BOOK  II. 

The  loss  occasionally  attaches  to  some  period  of  former  life. 
"  A  clergyman,  on  recovering  from  an  apoplectic  attack,  was 
found  to  have  lost  the  recollection  of  exactly  four  years  ;  every 
thing  that  occurred  before  that  period  he  remembered  perfectly. 
He  gradually  recovered."*  Another  patient,  who  had  been 
for  some  ten  or  twelve  years  in  Edinburgh,  recollected  nothing 
of  that  period  of  his  life  ;  on  the  contrary,  the  earlier  portion, 
which  had  been  passed  in  another  country,  was  well  remem- 
bered by  him. — Lately,  a  celebrated  Russian  astronomer  for- 
got, in  turn,  the  events  of  the  previous  day,  then  those  of  the 
year,  then  those  of  the  years  last  past,  and  so  on,  the  chasm 
gradually  increasing,  till  at  last  he  could  only  recollect  the 
events  of  his  childhood.  His  case  was  considered  hopeless ; 
but  by  a  sudden  stop  and  unforeseen  return,  the  blank  filled 
up  in  an  inverted  manner ;  the  events  of  his  youth  first  reap- 
pearing, then  those  of  his  manhood,  and  finally,  the  more 
recent,  those  of  the  previous  day.  His  memory  was  wholly 
restored  at  the  time  of  his  death. 

Gradual  recoveries  like  these  have  also  been  observed  after 
violent  falls ;  and  the  fissure  in  the  memory  closes  up  some- 
times from  one  end,  sometimes  from  the  other.  "  Some  years 
ago,"  says  Abercrombie,f  "  I  saw  a  boy  who  had  fallen  from 
a  wall,  and  struck  his  head  against  a  stone  which  lay  at  the 
foot  of  it.  He  was  carried  home  in  a  state  of  insensibility, 
from  which  he  soon  recovered,  but  without  any  recollection 
of  the  accident.  He  felt  that  his  head  was  hurt,  but  he  had 
no  idea  how  he  had  received  the  injury.  After  a  short  time 
he  recollected  that  he  had  been  on  the  top  of  a  wall,  and  had 
fallen  from  it  and  struck  against  the  stone,  but  -could  not  re- 
member where  the  wall  was.  After  some  time  longer,  he  re- 
covered the  recollection  of  all  the  circumstances."  Others 
when  injured  forget  the  accident  only,  and  not  the  circum- 
stances ;  others  the  circumstances  only,  but  not  the  accident. 
— Sometimes  the  alteration  is  still  stranger,  and  affects  a  cer- 
tain class  of  associations  only.  "  A  lady,:}:  after  an  apoplectic 
attack,  recovered  correctly  her  ideas  of  things,  but  could  not 


*  "  Inquiry  into  the  Intellectual  Powers,"  p.  151.  f  Ibid>  P-  J4°. 

J  Ibid.,  p.  149. 


CHAP.  II.]    REVIVAL  AND  OBLITERATION  OF  IMAGES.  g/ 

name  them.  In  giving  directions  respecting  family  matters, 
she  was  quite  distinct  as  to  what  she  wished  to  be  done,  but 
could  make  herself  understood  only  by  going  through  the 
house,  and  pointing  to  the  different  articles. — A  gentleman 
could  not  be  made  to  understand  the  name  of  an  object  if  it 
was  spoken  to  him,  but  understood  it  perfectly  when  it  was 
written.  His  mental  faculties  were  so  entire  that  he  was  en- 
gaged in  most  extensive  agricultural  concerns,  and  he  man- 
aged them  with  perfect  correctness  by  means  of  a  remarkable 
contrivance.  He  kept  before  him  in  the  room  where  he 
transacted  business,  a  list  of  the  words  which  were  most  apt 
to  occur  in  his  intercourse  with  his  workmen.  When  one  of 
these  wished  to  communicate  with  him  on  any  subject,  he 
first  heard  what  the  workman  had  to  say,  but  without  under- 
standing him  further  than  simply  to  catch  the  words.  He 
then  turned  to  the  words  in  his  written  list,  and  whenever 
they  met  his  eye  He  understood  them  perfectly."* 

This  suppression  of  ordinary  aptitudes  explains  the  revival 
of  lost  aptitudes.  One  particular  new  organic  disposition  may 
be  unfavorable  to  the  first ;  and  so,  some  other  new  organic 


*  See  other  analogous  facts  in  the  "  Dictionnaire  d'Histoire  Naturelle,"  pub- 
lished by  M.  Guerin,  in  an  article  by  Grimaud  de  Caux. — (Duval  Jouve,  "  Logique," 

P-  159- 

"  A  man  of  sixty,  in  good  health,  who  had  had  an  ulcer  in  his  leg  for  a  con- 
siderable time,  permitted  it  to  become  closed.  Before  long  he  had  a  slight  attack 
of  apoplexy,  and  this  was  followed  by  a  loss  of  memory,  first  of  certain  words,  then 
of  the  French  language.  The  remarkable  thing  was  that  he  recollected  perfectly 
the  Piedmontese  language. 

"A  man  of  science  on  starting  for  Greece  was  thrown  out  of  his  carriage  ;  a 
box,  fortunately  not  a  yery  heavy  one,  fell  on  his  head  ;  he  suffered  no  pain,  and 
the  skin  was  not  broken  ;  but  he  completely  forgot  where  he  had  ccme  from,  the 
object  of  his  journey,  the  day  of  the  week,  the  dinner  he  had  just  made,  and  all  his 
acquired  knowledge.  In  fact,  he  had  forgotten  the  names  of  his  relations  and 
friends,  and  could  only  recall  his  own,  those  of  his  children,  and  the  symbol  of 
the  Trinity.  He  was  replaced  in  the  carriage,  in  order  that  assistance  might  be 
obtained,  and,  after  half  an  hour's  jolting  over  a  stony  road,  suddenly  recovered 
himself." 

Page  162 — "  Some  persons  forget  proper  names  ;  others,  like  Doctor  Brousson- 
nais.  substantives.  Dietrich  tells  the  story  of  a  man  who,  while  recollecting  facts 
had  forgotten  half  his  words.  There  are  instances  of  foreign  languages,  the  facts 
of  history,  dates,  etc.,  being  entirely  forgotten,  while  other  things  were  recol- 
lected." 


88  OF  IMAGES.  [BOOK  II. 

disposition  may  be  favorable  to  the  second.  The  first  cease 
to  be  active,  like  a  nerve  suddenly  paralysed ;  the  second  be- 
come active  again,  like  a  paralysed  nerve  suddenly  electrified. 
We  have  seen  an  instance  of  this  in  the  case  of  the  ignorant 
young  girl  who,  in  her  delirium,  recited  passages  of  Greek 
and  rabbinical  Hebrew  ;  in  the  servant  who,  when  seized  with 
fever,  spoke  Welsh,  which,  when  well,  she  did  not  understand. 
"  A  man,"  says  Abercrombie,  "  born  in  France,  had  spent  the 
greater  part  of  his  life  in  England,  and  for  many  years  had  en- 
tirely lost  the  habit  of  speaking  French.  When  under  the  care 
of  Mr.  Abernethy  for  an  injury  of  the  head,  he  always  spoke 
French."*  In  other  cases  a  similar  revival  as  to  other  lan- 
guages has  been  observed.  "  An  eminent  medical  friend," 
says  the  same  author,  "  informs  me  that  during  fever,  without 
any  delirium,  he  on  one  occasion  repeated  long  passages  from 
Homer,  which  he  could  not  do  when  in  health."  Another 
person,  who,  when  well,  had  no  capacity  for  music,  and  had 
almost  forgotten  the  Gaelic  language,  sang,  during  an  illness, 
Gaelic  songs,  and  that  with  great  precision,  though  the  melody 
was  a  difficult  one,  and  he  had  previously  been  utterly  incapa- 
ble of  singing  it. 

Let  us  now  conceive  the  existence  in  the  same  person  of 
two  distinct  states,  such  as  we  have  been  describing ;  let  us 
suppose  that  in  the  first  a  certain  group  of  images,  in  the 
second,  some  other  group,  can  alone  revive,  what  will  happen 
if  in  the  two  states  the  general  organic  disposition  is  different, 
and  if  this  difference  is  a  clearly  marked  one  ?  The  individual 
will  have  two  memories,  the  first  recalling  only  the  events  of 
the  first  state,  and  the  second  recalling  only  .the  events  of  the 
second  state.f  A  young  American  lady,  says  Macnish,^:  after 


*  Abercrombie,  op.  cit.  140,  142. 

f  "  When  people  have  been  twice  hypnotized,  we  find  that  they  forget  complete- 
ly when  they  wake  the  acts  and  thoughts  artificially  produced,  and  recover  perfect 
recollection  of  them  on  re-entering  the  artificial  state.  Mr.  Braid  mentions  having 
seen  intelligent  persons  who  could  recollect  exactly  and  minutely  all  that  had 
happened  during  a  state  of  sleep  six  years  before,  and  who  narrated  this  whenever 
they  were  hypnotized,  while,  when  awake,  they  had  no  recollection  of  it." — "  De 
la  Folie  Artificielle,"  Dr.  Tuke/"  Annales  Medico-Psychologiques,"  46  Serie,  vi. 
P-  271. 

\  Macnish,  p.  I  3,  n.  citing  from  "  The  Medical  Repository."     New  York. 


CHAP.  II.]  REVIVAL  AND  OBLITERATION  OF  IMAGES.  go 

a  prolonged  sleep,  lost  the  recollection  of  all  she  knew.  She 
was  obliged  to  learn  again  how  to  spell,  to  read,  to  write,  to 
calculate,  and  to  know  the  persons  and  objects  around  her. 
A  few  months  after,  she  was  again  seized  with  a  deep  sleep, 
and  when  she  woke  she  was  restored  to  the  state  she  was  in 
before  the  first  sleep,  having  all  the  knowledge  and  recollec- 
tions of  her  youth ;  but  on  the  other  hand,  having  entirely 
forgotten  all  that  had  passed  between  the  two  attacks.  "  Dur- 
ing four  years  and  upwards  she  has  passed  periodically  from 
one  state  to  the  other,  always  after  a  long  and  sound  sleep 

The  former  condition  of  her  existence  she  now  calls 

the  Old  State,  and  the  latter  the  New  State ;  and  she  is  as 
unconscious  of  her  double  character  as  two  distinct  persons 
are  of  their  respective  natures.  For  example,  in  her  old  state 
she  possesses  all  the  original  knowledge ;  in  her  new  state 
only  what  she  acquired  since.  If  a  lady  or  gentleman  be  intro- 
duced to  her  in  the  old  state,  or  vice  versa  (and  so  of  all  other 
matters),  to  know  them  satisfactorily  she  must  learn  them  in 
both  states.  In  the  old  state,  she  possesses  fine  powers  of 
penmanship,  while  in  the  new,  she  writes  a  poor  awkward 
hand,  not  having  had  time  or  means  to  become  expert.  Both 
the  lady  and  her  family  are  now  capable  of  conducting  the 
affair  without  embarrassment.  By  simply  knowing  whether 
she  is  in  the  old  or  new  state,  they  regulate  the  intercourse, 
and  govern  themselves  accordingly." — This  double  life  is  often 
found  in  somnambulists.*  The  majority  of  them  forget  on 
awaking  all  they  have  done  in  their  sleep,  and  are  surprised 
to  find  themselves  out  of  bed  or  in  the  street.  But  this  forget- 
fulness  frequently  ceases  on  a  second  attack.  "  The  somnam- 
bulist," says  M.  Maury,  "  takes  up  again  the  chain  of  ideas 
interrupted  while  he  was  awake.  Thus  Dr.  Mesnet's  patient 
carried  out,  during  an  attack,  projects  of  suicide  she  had  con- 
ceived in  a  previous  attack  and  forgotten  during  the  lucid  in- 
terval ;  in  the  second  attack  she  recalled  all  the  circumstances 
of  the  first.  M.  Macario  has  cited  a  very  significant  example 
of  a  young  girl  who  was  violated  during  a  fit  of  somnambulism, 


*  Maury,  "  Du  Sommeil,"  210.    Todd,  "  Cyclopaedia,"  Article  "  Sleep."     Fuel, 
"  Memoire  sur  la  Catalepsie." 


OO  OF  IMAGES.  [BOOK  II. 

and  who,  on  awaking,  had  no  recollection  or  consciousness  of 
what  had  happened.  It  was  only  in  a  new  fit  that  she  related 
to  her  mother  the  outrage  committed  upon  her."  In  these 
two  instances,  the  wakeful  state  only  recalled  the  wakeful 
state  ;  the  state  of  somnambulism  only  recalled  the  state  of 
somnambulism,  and  each  of  the  two  alternate  lives  formed  a 
separate  whole. 

Correspondences  and  separations  'like  these,  but  partial 
and  temporary,  are  met  with  in  ordinary  life.  "  Mr.  Combe 
mentions  the  case  of  an  Irish  porter  to  a  warehouse,  who,  in 
one  of  his  drunken  fits,  left  a  parcel  at  the  wrong  house,  and 
when  sober  could  not  recollect  what  he  had  done  with  it ;  but 
the  next  time  he  got  drunk,  he  recollected  where  he  had  left 
it,  and  went  and  recovered  it."*  M.  Maury  again  mentions 
cases  of  dreams  forgotten  when  awake,  and  recalled  in  a  new 
state  of  sleep. — On  the  other  hand,  our  ordinary  memory  re- 
calls only  half  our  states.  We  recall  our  thoughts  of  yester- 
day, but  not  those  of  the  night  while  we  were  asleep  ;  how- 
ever vivid  they  may  have  been,  even  when  they  have  pro- 
voked actions  or  the  beginnings  of  actions,  cries,  gestures,  and 
all  that  an  uneasy  man  does  in  his  sleep,  it  is  very  unusual, 
for  us  to  be  able  on  waking  to  recover  any  portions  of  them.f 
It  is  a  strange  thing,  we  start  from  an  intense  dream,  full  of 
emotions ;  and  it  would  seem  that  so  violent  a  state  ought  to 
be  easily  reproduced,  even  after  a  considerable  time.  Not  at  all ; 
after  two  or  three  minutes  the  objects  so  clearly  perceived 
die  away  in  clouds ;  and  these  clouds  vanish ;  half  an  hour 
afterwards  I  shall  be  scarcely  able  to  relate  my  dream ;  if  I 
want  to  remember  it  later  on,  I  am  obliged  to  write  it  down 
at  once. — The  fact  is  that  the  physiological  state  and  the  cir- 
culation of  blood  in  the  brain  are  not  alike  in  sleep  and  when 
awake,  and  the  second  state,  favorable  to  the  recall  of  its 
own  images,  is  not  favorable  to  the  recall  of  the  images  of 
the  first  state. 

But  whatever  be  the  phenomenon,  rudimentary  and  nor- 
mal or  abnormal  and  complete,  it  shows  how  our  images, 
by  connecting  themselves,  make  up  the  group  which  in  liter- 


*  Macnish,  "  The  Medical  Repository,"  p.  55,  n.  f  Ibid. 


CHAP.  II.]  REVIVAL  AND  OBLITERATION  OF  IMAGES.  9! 

ary  and  judicial  language  we  call  the  moral  personality.  If 
two  groups  are  distinctly  severed,  so  that  no  element  of  the 
one  calls  up  any  element  of  the  other,  we  shall  have,  as  in  the 
case  of  the  lady  cited  by  Macnish,  two  moral  personalities  in 
the  same  individual.  If  in  one  of  the  two  states  the  images 
have  exact  and  delicate  associations,  if  as  we  see  in  the  cases 
of  many  somnambulists,*  superior  aptitudes  show  themselves, 
if,  as  we  observe  in  drunkenness  and  after  many  illnesses,  the 
passions  take  another  degree  and  another  direction,  not  only 
will  these  moral  personalities  be  distinct,  but  there  will  be 
enormous  disproportions  and  contradictions  between  them. — 
No  doubt,  though  among  somnambulists,  persons  hypnotized 
and  in  states  of  ecstasy,  similar  contrasts  distinguish  the  or- 
dinary from  the  abnormal  life,  these  two  lives  are  not  clearly 
nor  entirely  distinct ;  some  images  of  the  one  always,  or  near- 
ly always,  introduce  themselves  into  the  other ;  and,  when 
man  is  concerned,  the  supposition  we  have  made  remains 
simply  a  conception  of  the  mind. — But,  among  animals,  we 
meet  with  instances  in  which  it  is  exactly  applicable ;  such  as 
that  of  the  patrachians,  and  of  insects  which  undergo  meta- 
morphoses. Their  organization  and  nervous  system  bring 
forward  in  turn,  by  their  transformations,  two  or  three  moral 
personalities  in  the  same  individual :  in  the  chrysalis,  the 
larva,  and  the  butterfly,  instincts,  images,  recollections,  sen- 
sations, and  appetites,  are  all  different ;  the  silkworm  which 
spins,  and  its  moth  which  flies,  the  voracious  larva  of  the  cock- 
chafer, with  its  terrible  apparatus  of  stomachs,  and  the  cock- 
chafer itself,  are  two  distinct  states  of  the  same  being  at  two 
epochs  of  its  development,  two  distinct  systems  of  sensations 
and  images  engrafted  on  two  distinct  forms  of  the  same  ner- 
vous substance. — If  a  sleep  like  that  of  the  chrysalis  were  to 
overtake  us  in  the  midst  of  our  life,  and  if  we  were  to  awake 
with  an  organization  and  a  nervous  machinery  as  much  trans- 
formed as  that  of  the  worm  which  has  become  a  butterfly, 
the  break  between  our  two  moral  personalities  would  evident- 
ly be  as  great  in  our  case  as  with  it. — The  reader  can  now  see 
the  infinite  consequences  of  that  property  of  our  sensations 


*  Maury,  "The  Medical  Repository,"  p.  125. 


g2  OF  IMAGES.  [BOOK  II« 

and  images  which  we  have  termed  aptitude  for  revival ;  it  as- 
sembles in  groups  our  internal  events,  and  in  addition  to  the 
continuity  of  physical  being  constituted  by  permanence  of 
form,  it  constitutes,  by  the  return  and  connexion  of  images, 
the  continuity  of  the  moral  being. 


CHAP.  I.j  SENSATIONS  OF  HEARING,  ETC.  03 


BOOK   III. 

OP    SENSATIONS. 

CHAPTER  I. 

OF  SENSATIONS  OF  HEARING  AND  THEIR  ELEMENTS. 

I.  BY  reduction  upon  reduction  we  have  arrived  at  a  fact, 
primitive  and  apparently  irreducible,  of  which  all  the  rest, 
whether  images  or  ideas,  are  but  repetitions  more  or  less  trans- 
formed and  disguised.  I  mean  sensation,  and  before  defining 
it,  that  is  to  say,  before  showing  its  nature,  we  must  first  de- 
scribe it,  that  is,  must  distinguish  it  and  bring  it  to  light,  from 
among  the  heap  of  facts  in  which  it  is  comprised. — When  a 
cutting  instrument  is  plunged  into  our  flesh,  we  feel  pain,  and 
this  pain,  taken  by  itself  and  alone,  is  a  sensation  strictly  so- 
called.  There  are  a  number  of  such  facts,  similar  in  nature, 
though  differing  in  kind  and  degree  ;  such  are  the  sensations 
of  contact,  of  pressure,  of  tickling,  usually  excited  in  us  when 
an  external  body  touches,  in  a  particular  way,  certain  portions 
of  our  bodies  ;  such  are  the  sensations  of  temperature  pro- 
duced when  a  certain  degree  of  heat  is  added  to  or  taken  away 
from  our  ordinary  temperature  ;  such  are  the  sensations  of  mus- 
cular activity,  so  called  from  their  apprising  us  of  the  tension 
or  relaxation  of  our  muscles ;  such,  in  short,  are  the  sensations 
excited  in  us  by  the  particular  juices  of  an  object  we  taste, 
by  the  volatile  particles  of  an  object  we  smell,  by  the  vibrations 
of  the  air  which  strike  our  organs  of  hearing,  by  the  vibrations 
of  light  which  strike  our  organs  of  sight,  and  which  we  com- 
monly call  sensations  of  taste,  of  smell,  of  sound,  and  of  color. 

Many  of  these  names  are  ambiguous,  and  the  words  taste, 
smell,  sound,  color,  heat,  sometimes  denote  a  property,  more 
or  less  unknown  to  us,  of  surrounding  bodies,  of  liquid  or  volatile 


94  OF  SENSATIONS.  [BOOK  III. 

particles,  of  vibrations  of  the  air  or  of  light ;  sometimes,  the 
well-known  kind  of  sensations  which  these  bodies,  particles,  and 
vibrations,  excite  in  us.  But  the  distinction  is  easily  made ; 
for  the  property  appertains  to  the  object  and  not  to  us, 
while  the  sensation  appertains  to  us  and  not  to  the  object. 
Lemon-juice  has  an  acid  taste ;  this  means  that  it  possesses 
an  unknown  property  of  exciting  in  us  a  well-known  sensation, 
that  of  an  acid  taste.  This  sheet  of  paper  is  white  :  this  means 
that  by  virtue  of  its  particular  texture,  this  sheet  of  paper, 
when  in  the  light,  excites  in  us  the  sensation  of  the  color  white. 
— Two  other  distinctions  less  readily  made  are  no  less  necessa- 
ry. When  we  experience  a  sensation,  we  localize  it ;  we  refer, 
such  a  pain,  such  a  feeling  of  heat,  such  a  sensation  of  contact, 
to  the  hand,  to  the  leg,  to  such-and-such  a  part  of  the  body, 
such  a  sensation  of  smell  to  the  interior  of  the  nose,  such  a 
sensation  of  taste  to  the  palate,  to  the  tongue,  to  the  back  of 
the  mouth.  But,  as  we  shall  see  later  on,  there  is  here  an  ul- 
terior operation  engendered  by  experience  ;  a  group  of  images 
has  combined  with  the  sensation  to  attribute  to  it  this  posi- 
tion ;  this  group  gives  it  a  situation  which  really  it  has  not, 
and,  in  general,  places  it  at  the  extremity  of  the  nerve  whose 
action  excites  it.  Sometimes  again,  a  second  operation  re- 
moves it  to  a  still  more  distant  place  ;  sounds  and  colors,  which 
are  sensations  only,  at  present  appear  to  us  situated,  not  in  our 
organs,  but  at  a  distance,  in  the  air,  or  on  the  surface  of  ex- 
ternal objects  ;  the  reader  will  see,  when  we  examine  external 
perception,  how  the  education  of  the  senses  produces  this  ap- 
parent recoil.  Meanwhile,  to  understand  the  sensation  prop- 
erly, we  must  separate  it  from  this  accompaniment,  must  lay 
aside  the  appendages  which  time  has  attached  to  it,  and  con- 
sider it  in  its  simple  primitive  state. — Finally,  we  must  distin- 
guish it,  at  least  provisionally,  from  the  state  of  the  nerve  and 
nervous  centres  by  whose  action  it  is  produced.  It  is  true 
that  this  state  is  the  sufficient  and  necessary  condition  of  the 
sensation,  but  their  identity  is  not  clear ;  at  first  sight  they 
differ,  and  certainly  are  not  known  to  us  to  the  same  extent 
or  in  the  same  way.  For  the  sensation  is  perceived  directly, 
completely,  and  at  once,  but  the  action  of  the  nervous  system 
is  proved  indirectly,  incompletely,  and  very  slowly;  an  infinite 


CHAP.  I.]  SENSATIONS  OF  HEARING,  ETC. 


95 


amount  of  anatomical  and  physiological  research  was  required 
to  teach  us  that  the  sensation  depended  on  it  ;  even  now  we 
are  wholly  ignorant  of  what  it  consists,  whether  it  is  a  propa- 
gated vibration,  an  electric  current,  a  chemical  change,  or  what 
else  it  may  be.  Strict  method  then  requires  us,  for  the  pres- 
ent, to  leave  it  on  one  side  and  to  study  in  the  first  place  the 
sensation  apart. — So  circumscribed,  it  is  that  primary  inter- 
nal event,  directly  known  to  us,  accompanied  by  images  as- 
sociated with  it  and  localizing  it,  and  excited  by  a  certain 
state  of  the  nerves  and  nervous  centres,  a  state  unknown  to 
us,  and  consequent,  in  general,  on  the  action  of  external  ob- 
jects. 

II.  Here  we  have  a  fact  of  supreme  importance;  for  its 
diversities  and  arrangements  form  the  material  of  all  our  knowl- 
edge. When  we  consider  closely  any  one  of  our  conceptions 
— that  of  a  plant,  an  animal,  a  mineral — we  find  that  the  primi- 
tive threads  of  which  it  is  woven  are  sensations,  and  sensations 
only ;  we  shall  see  the  proof  of  this  later  on.  But  we  have  it 
already,  if  we  recollect  that  our  images  are  only  reviving  sen- 
sations, that  our  ideas  are  nothing  more  than  images  which 
have  become  signs,  and  that  thus  this  elementary  tissue  sub- 
sists, in  a  more  or  less  disguised  form,  at  all  stages  of  our 
thought. — These  primitive  threads  are  of  different  kinds.  Sen- 
sations have  long  been,  more  or  less  happily,  distributed,  in 
the  ordinary  method,  into  classes  and  sub-classes  ;  first,  ac- 
cording to  the  services  they  render  us  ;  then,  according  to  the 
particular  circumstances  in  which  they  arise,  and  the  parts  in 
which  the  associated  images  induce  us  to  place  them;  and 
lastly,  according  to  such  rough  similarities  as  internal  observa- 
tion can  find  in  them.* — A  first  group  has  been  formed  of 
those  which  denote  different  states  of  the  body  in  health  or 
sickness,  and  are  stimulants  to  action,  rather  than  elements  of 
knowledge ;  these  have  been  called  sensations  of  organic  life, 
and  have  been  divided  into  genera  and  species,  according  to 
the  organs  or  functions  which  excite  them  ;  in  one  class,  effort, 
fatigue,  and  the  different  pains  occasioned  by  states  of  the 


*  Gerdy,  "  Physiologic  des  Sensations   et  de  1'Intelligence."     Bain,  "  Senses 
and  Intellect,"  87,  250. 


96  OF  SENSATIONS.  [BOOK  III. 

muscles,  bones,  and  tendons  ;  in  another,  nervous  exhaustion 
and  the  nervous  sufferings  occasioned  by  special  states  of  the 
nerves ;  in  another,  the  sufferings  of  thirst  and  hunger  occa- 
sioned by  certain  states  of  circulation  and  nutrition  ;  in  another, 
suffocation  and  the  peculiar  state  of  uneasiness  occasioned  by 
a  certain  state  of  the  respiration  ;  in  another  again,  sensations 
of  cold  and  heat  occasioned  by  a  general  state  of  all  the  organs  ; 
finally,  in  another,  those,  as  of  digestion,  occasioned  by  states 
of  the  alimentary  canal. — By  the  side  of  this  group  a  second 
has  been  formed,  whose  earlier  classes  come  in  contact  with 
the  latter  ones  of  the  first  group  ;  it  comprises  those  sensations 
which  do  not  acquaint  us  with  the  healthy  or  unhealthy  states 
of  our  bodies,  but  are  elements  of  knowledge,  rather  than  stim- 
ulants to  action.     These  we  call  sensations  of  intellectual  life, 
and  divide  them,  according  to  the  special  organs  exciting  them, 
into  sensations  of  smell,  of  taste,  of  touch,  of  hearing,  and  of 
sight.     In  each  of  these  genera  there  are  species.     In  sensa- 
tions of  taste,  distinctions  are  drawn  between  relishes*  allied 
to  alimentary  sensations,  and  provoking  appetite  or  disgust, 
according  to  the  state  of  the  stomach,  and  tastes  strictly  so 
called,  and  themselves  divisible  into  many  groups,  such  as  bit- 
ter, sweet,  salt,  alkaline,  acid,  astringent.     In   sensations   of 
smell,  distinctions  are  similarly  drawn  between  smells  connect- 
ed with  the  respiratory  sensations,  compounded  or  mingled 
with  a  sensation  of  freshness  or  closeness,  and  smells  strict^ 
so  called,  and  themselves  divisible  into  perfumed,  foetid,  pun- 
gent, ethereal,  etc.     Similar  classifications  are  adopted  in  the 
distribution  of  the  sensations  of  the  other  senses  ;  and  slight 
differences  will   be    found   in   them,  according  to   different 
authors.f 

But  these  differences  are  of  little  importance ;  all  they 
afford  us  is  a  survey  of  the  subject ;  we  have  constructed  a 
convenient  repository,  with  compartments  enabling  us  to  lay 
our  hands  readily  on  the  sensation  we  wish  to  consider ;  but 
this  is  all.  We  do  not  know  what  the  sensation  itself  consists 


*  Relishes  distinguished  from  tastes. — Bain,  "  Senses  and  Intellect." 
f  See  the  physiological  works  of  Longet,  Mueller,  Carpenter,  Todd  and  Bow- 
man, etc. 


CHAP  I.]  SEATSATIONS  OF  HEARING,  ETC. 


97 


in  ;  if  we  consider  some  particular  one — for  instance,  the  smell 
of  a  rose — we  find  it  comprised  in  the  class  of  perfumed  odors 
with  that  of  the  lily,  the  violet,  musk,  and  an  infinite  number 
more.  But  while  thus  distinguishing  it  from  others,  we  cannot 
say  in  what  it  differs  from  them ;  we  vaguely  perceive  that  it 
is  a  stronger  smell  than  that  of  the  violet,  and  not  so  strong 
as  that  of  the  lily ;  our  knowledge  is  reduced  to  this.  We 
cannot  enumerate  and  state  its  elements  as  precisely  as  if  it 
were  a  question  of  two  kinds  of  minerals  or  vegetables ;  we 
have  no  elements  of  comparison,  like  magnitude,  form,  posi- 
tion, number,  to  sum  up  and  connect  together ;  mathematical 
and  geometrical  qualities,  which  serve  as  a  foundation  for  the 
physical  sciences,  fail  us  here. — And  here,  again,  the  ground 
from  which  we  started  to  construct  the  moral  sciences  fails  us 
also.  We  have  not  here  those  common  elements,  images, 
representations,  general  ideas,  to  which  different  human  in- 
ventions and  social  combinations  -may  be  reduced.  We  are 
at  the  central  point  of  knowledge,  a  kind  of  link  placed  be- 
tween the  infinite  ramifications  of  the  branch  and  those  of  the 
root,  enclosing  in  its  narrow  band  the  origin  of  the  fibres  which 
above  and  below  make  up,  by  their  multiplication  and  their 
arrangement,  the  entire  plant. — But  it  is  precisely  because 
our  sensations  are  elements  of  which  all  the  rest  is  composed, 
that  we  are  unable  to  decompose  them  like  the  rest ;  we  can- 
not find  elements  of  these  elements.  We  are  able  to  show 
how  with  them  we  form  images,  representations,  and  general 
ideas — how  with  them  we  form  notions  of  magnitude,  position, 
form,  and  number  ;  but  as  to  how  they  are  themselves  formed, 
this  we  do  not  know. 

It  seems,  then,  that  they  escape  from  science  ;  and,  in  fact, 
when  we  read  works  treating  of  them,  we  learn  little  but  what 
we  knew  before ;  when  we  close  the  book,  we  find  them  well 
arranged  in  our  mind,  and  that  is  all.  If  we  are  taught  any 
thing,  it  is  in  another  department,  in  physiology  and  anatomy, 
by  the  knowledge  of  the  apparatus,  organs,  and  movements 
on  which  they  depend.  Even  with  the  highest  hopes,  all  the 
horizon  shows  us  is  a  more  extended  knowledge  of  these  ap- 
paratus, movements,  and  organs  ;  perhaps  some  day,  if  the 
microscope  becomes  more  powerful,  when  the  theories  of  elec- 
7 


^8  OF  SENSATIONS.  [BOOK  III. 

tricity,  organic  chemistry,  and  molecular  physics  have  made 
some  great  advance,  experimentalists  may  be  able  to  distin- 
guish the  different  primitive  fibres  in  a  nerve,  may  define  ex- 
actly their  internal  movements,  explain  the  structure  of  the 
nervous  centres,  and  state  precisely  what  change  of  state  the 
action  of  the  nerve  excites  there. — Under  the  most  favorable 
circumstances,  and  supposing  the  science  complete,  we  should 
arrive  at  a  mathematical  formula  enabling  us  to  sum  up  in 
some  one  law  the  different  positions  and  relations  of  the  nerv- 
ous particles. — But  these  advances,  great  as  we  imagine  them 
to  be,  add  nothing  to  our  idea  of  sensations ;  they  enlighten 
us  as  to  their  conditions,  but  not  as  to  them.  If  you  describe 
to  me  the  molecular  movement  produced  in  the  glosso-pha- 
ryngeal  nerves,  and  the  other  molecular  movements  conse- 
quently developed  in  the  nervous  centres  when  a  solution  of 
sugar  or  of  colocynth  passes  over  my  tongue  or  throat ;  you 
will  not  teach  me  any  thing  as  to  the  nature  of  the  sensations 
of  sweet  and  bitter.  I  shall  know  the  circumstances  under 
which  they  arise,  I  shall  not  know  their  elements,  or  even  if 
they  have  any.  The  most  I  shall  perhaps  find  will  be  some 
law  connecting  the  intensity  of  bitterness  with  some  form  or 
other  of  molecular  movement,  resembling  the  law  which  makes 
the  acuteness  of  a  sound  increase  with  the  number  of  vibra- 
tions transmitted  to  the  auditory  nerve. 

The  matter  becomes  still  clearer  when  we  compare  two 
sensations,  not  of  the  same,  but  of  different  senses,  even  when 
both  are  produced  by  the  same  external  cause ;  for  instance, 
the  tickling  and  the  sound  produced  by  the  same  vibrations 
of  the  air,  the  painful  feeling  and  luminous  circle  produced  by 
the  same  compression  of  the  eye,  the  sensations  of  dazzling 
light,  of  hissing  sound,  of  shock,  or  tingling,  produced  by  the 
'  same  electricity  applied  to  different  senses.  Each  one  of  these 
senses  forms  a  region  apart ;  neither  smell,  nor  taste,  nor  color, 
nor  sound,  nor  sensation  of  contact,  can  be  reduced  to  any 
other ;  and,  in  every  sense,  there  are  many  regions  no  less 
distinct  from  one  another ;  bitter,  salt,  and  sweet  tastes,  like 
blue,  red,  and  yellow  colors,  like  sensations  of  heat,  pressure, 
and  tickling,  seem  equally  irreducible  to  one  another. — The 
only  intrinsic  quality  which  we  find  to  be  common  to  all  these 


CHAP.  I.]  SENSATIONS  OF  HEARING,  ETC.  gg 

distinct  domains,  is  the  degree  of  intensity ;  every  sensation 
is  capable  of  increase  or  decrease  ;  it  is  a  stage  in  a  magnitude  ; 
smell,  taste,  sound,  brightness,  pressure,  may  all  be  more  or 
less  strong.  So  it  is  with  the  secondary  groups  comprised 
in  the  principal  ones ;  every  special  sensation,  that  of  bitter- 
ness, of  tickling,  of  blue,  has  a  maximum  and  a  minimum,  on 
passing  which,  it  ceases,  or  becomes  of  another  kind. — But 
each  of  them  is  a  kind  of  simple  body  which,  though  capable 
in  itself  of  increase  or  diminution,  is  not  convertible  into  any 
of  the  others.  In  chemistry  there  are  sixty-one  such  ;  there 
are  many  more  for  every  sense,  for  instance,  for  smell  or  taste  ; 
for  there  is  scarcely  a  single  volatile  odorous  matter  that  does 
not  form  a  type  apart ;  we  are  sometimes  able  to  arrange  two, 
or  at  most  three  other  sensations,  together  with  the  sensation 
it  excites,  as  the  smell  of  garlic  and  of  the  vapor  of  arsenic 
with  the  smell  of  tin ;  thus  the  species  are  innumerable,  and 
classes  scarcely  exist ;  as  we  see  on  attempting  to  count  the 
smells  of  perfumed  plants  in  a  garden,  or  of  disagreeable  gases 
in  a  laboratory. — Thus  it  would  seem  that  at  the  commence- 
ment of  psychology,  we  are  obliged  to  set  down  a  very  great 
number  of  facts  as  mutually  irreducible,  just  as  simple  bodies 
in  chemistry,  as  the  species  of  animals  in  zoology,  or  of  vege- 
tables in  botany,  but  with  this  special  disadvantage,  that  while 
in  chemistry,  in  botany,  and  zoology,  differences  and  resem- 
blances are  constituted  by  homogeneous  and  precise  elements, 
number,  force,  and  form,  in  the  sensations,  no  such  element 
can  be  isolated,  and  we  are  driven  to  the  unreasoning  affirma- 
tion of  certain  rough  likenesses  and  to  the  dry  statement  of 
an  indefinite  number  of  undefinable  differences. 

III.  Sensations,  however,  have  elements,  as  will  appear 
from  various  examples.  We  all  know  that  in  a  musical  chord 
there  are  two  notes,  that  an  ordinary  color  is  made  up  of 
many  colors  ;  we  must  advance  a  step,  and  see  if  those  sensa- 
tions of  sound,  color,  and  the  rest,  which  appear  to  us  sim- 
ple, are  not  themselves  composed  of  more  simple  sensations. 
— Psychology  is  at  present  confronted  with  sensations  pro- 
fessedly simple,  just  as  chemistry  was,  at  its  outset,  with  pro- 
fessedly simple  bodies.  In  fact,  in  its  early  stages,  observa- 
tion, whether  internal  or  external,  perceives  compounds  only ; 


100  OF  SENSATIONS.  [BOOK  III. 

its  business  is  to  decompose  them  into  their  elements,  to  show 
the  different  groupings  these  elements  are  capable  of,  and  to 
construct  different  compounds  with  them.  The  chemist  shows 
that,  by  the  combination  of  a  proportion  of  nitrogen  with  one, 
two,  three,  four,  or  five,  proportions  of  oxgen,  we  form  pro- 
toxide of  nitrogen,  deutoxide  of  nitrogen,  nitrous  acid,  hypo- 
nitric  acid,  and  nitric  acid ;  five»substances  which,  to  ordinary 
observation,  have  nothing  in  common,  and  which,  neverthe- 
less, differ  only  in  the  number  of  proportions  of  oxgen  com- 
prised in  each  of  their  atoms.  The  psychologist  has  to  inquire 
whether,  by  combining  such-and-such  an  elementary  sensation 
with  one,  two,  three,  other  elementary  sensations,  by  approx- 
imating the  times  of  their  occurrence,  by  giving  them  a  longer 
or  shorter  duration,  by  communicating  to  them  a  greater  or 
less  intensity,  he  cannot  arrive  at  constructing  those  masses 
of  sensation  to  which  rude  consciousness  attains,  and  which, 
though  irreducible  to  her,  differ  only  in  the  duration,  prox- 
imity, magnitude,  and  number  of  their  elements. 

Now  there  is  a  group  of  sensations  in  which  a  complete 
reduction  can  be  effected — namely,  those  of  hearing ;  and  we 
may  legitimately  argue  from  these  to  others ;  the  partial  so- 
lution attained  indicates  a  general  solution  which  may  be  at- 
tained.— The  kinds  of  sounds  are  apparently  very  numerous  ; 
and  ordinary  observation  detects  in  them  many  seemingly 
simple  qualities.  Two  sounds  produced  by  the  same  instru- 
ment may  be  respectively  high  and  low.  Two  sounds  equally 
high  or  low  have  different  tones,  if  produced,  one  by  a  violin, 
and  the  other  by  a  flute.  Two  sounds  equally  high  or  low, 
and  of  the  same  tone,  may  be  more  or  less  loud  or  intense. 
Two  sounds  may  be,  the  one  musical,  the  other  unmusical ; 
that  is  to  say,  the  one  may  be  a  continuous  sensation,  all 
whose  parts  are  mutually  alike  ;  while  the  other  is  a  discontin- 
uous sensation,  and  made  up  of  parts  differing  from  one 
another.  Finally,  this  last  class  contains  many  kinds  appar- 
ently irreducible  to  one  another ;  explosions,  clangings,  grind- 
ings,  hummings,  rustlings,  which  we  can  only  denote  by  the 
body  and  external  condition  producing  them,  as  the  sound  of 
a  hammer,  of  a  glass,  of  a  piece  of  wood,  of  crumpled  paper, 
etc. — In  this  great  collection  we  distinguish  two  qualities 


CHAP.  I.]  SENSATIONS  OF  HEARING,  ETC.  IOI 

capable  of  degrees — intensity,  and  acuteness ;  in  these  respects, 
different  sounds  form  a  scale ;  in  all  other  respects,  they  are 
in  juxtaposition,  are  vaguely  related  to  one  another,  like  smells 
and  tastes,  without  it  being  possible  to  say  in  what  this  rela- 
tionship consists ;  tone,  for  instance,  like  noise,  is  a  thing  un- 
definable.  The  same  sol  played  with  the  same  strength 
on  a  clarionet,  a  flute,  a  violin,  a  horn,  a  bassoon,  borrows  a 
special  character  according  to  the  different  instruments ;  it  is 
more  piercing  on  the  violin,  more  brilliant  on  the  horn,  sweeter 
on  the  flute,  keener  on  the  clarionet,  more  veiled  on  the  bas- 
soon. But  none  of  these  adjectives  define  it ;  they  only  indi- 
cate some  distant  analogy  between  our  total  impression  and 
impressions  of  another  nature  ;  they  are  simply  literary  labels 
like  the  names  we  apply  to  perfumes,  when  we  call  the  smell 
of  the  heliotrope  delicate,  that  of  the  lily,  full  and  rich,  of 
musk,  penetrating,  etc.  These  epithets  tell  us  something  of 
our  sensation,  but  very  little  ;  in  no  case  do  they  tell  us  any 
thing  of  the  elementary  sensations,  of  which  our  whole  sensa- 
tion is  made  up. 

Fortunately,  students  of  physics  and  physiology  have  ad- 
vanced our  researches  while  pursuing  their  own  ;  and  their 
discoveries  as  to  undulations  and  the  nerves  enable  us  to  find 
what  we  are  seeking. — The  sensation  of  sound  is  excited  by 
the  concussion  of  the  acoustic  nerve,  occasioned,  in  most  cases, 
by  the  vibration  of  the  external  air ;  we  further  observe,  in 
fact,  that  when  precisely  similar  concussions  are  occasioned, 
precisely  similar  sensations  of  sound  are  produced.  This  is 
the  case  with  the  sirens  of  Cagniard  Latour  and  Helmholtz, 
and  the  wheel  of  Savart.  When  this  wheel  is  turned  at  a 
uniform  rate,  its  teeth,  which  are  at  equal  distances,  strike  a 
bar  in  passing  ;  arid  this  regular  succession  of  similar  concus- 
sions excites  a  regular  succession  of  similar  sensations  of  sound. 
Now,  while  the  wheel  turns  sufficiently  slowly,  the  sensations, 
being  discontinuous,  are  distinct ;  and  each  of  them,  being 
compound,  is  a  sound.  But  when  the  wheel  is  set  to  turn  fast 
enough,  a  new  sensation  arises,  that  of  a  musical  note.  It  dis- 
tinguishes itself  from  the  remains  of  the  noises  which  still  go 
on  and  continue  distinct,  and  stands  out  as  a  fact  of  a  different 
kind  ;  among  the  different  elementary  sensations  which  make 


IO2  OF  SENSATIONS.  [BOOK  III. 

up  each  sound,  there  is  one  which  the  operation  has  separated  ; 
and  this  now  ceases  to  be  distinct  from  the  similar  elementary 
sensation  following  in  each  of  the  succeeding  sounds.  All 
these  similar  sensations  now  combine  in  one  long  continuous 
sensation;  their  mutual  limits  are  effaced;  experience, just  as 
in  a  chemical  analysis,  has  extracted  an  elementary  sensation 
from  the  complex  group  in  which  it  was  included,  has  joined 
it  to  an  absolutely  similar  elementary  sensation,  and  formed  a 
new  compound,  the  sensation  of  musical  sound.* 

But  if,  among  musical  sounds,  we  choose  a  very  deep  one, 
for  instance,  the  lower  octave  of  the  organ,  we  see  that  the 
elementary  sensations,  though  still  forming  a  continuous  whole 
— which  they  must  do  for  the  sound  to  be  musical — neverthe- 
less remain  to  a  certain  extent  distinct.  "  The  lower  the 
note,  the  better  does  the  ear  distinguish  in  it  the  successive 
pulsations  of  the  air."f  It  is  then  not  much  removed  from  a 
buzzing,  that  is  to  say,  a  simple  noise.  We  distinguish  in  it 
elementary  sensations ;  we  recognize  that  each  of  them  con- 
sists in  a  swelling  and  a  dying  away,  that  is  to  say,  in  an  in 
crease  and  a  diminution  of  intensity ;  we  can  observe  the 
limits  of  each  one  of  them  ;  these  limits  are  but  half  effaced. 
We  find,  on  comparing  it  with  the  elementary  sensation  cor- 
responding to  a  more  acute  note,  that  it  occupies  a  greater 
length  of  time.  Again,  the  length  of  time  is  greater  between 
the  maximum  of  height  of  one  of  its  elementary  sensations, 
and  the  maximum  of  height  of  the  succeeding  one.  The  whole 
sensation  is  thus  composed  of  larger  molecules  and  more  dis- 
tant maxima.  This  is  why  we  call  it  a  fuller  or  heavier  sound. 
Here  we  perceive  the  elementary  sensation  whose  different 
combinations  are  sufficient  to  explain  all  the  sensations  of 
sound. 

Let  us  first  consider  musical  sounds.  We  know  by  acous- 
tics that  the  condition  of  a  sound  being  musical  is  that  there 
be  a  uniform  series  of  vibrations  of  the  air;  that  each  of  these 


*  Mueller  (tr.  Baly),  ii.  973  and  1298.  The  wheel  of  Savart  shows  us  that  a  sec- 
ond elementary  sensation  is  necessary  and  sufficient  to  effect  this  extraction  and  form 
the  new  compound. 

f  Helmholtz,  "  Conferences  Scientifiques  de  Bonn." — "  Revue  des  Cours  Scien- 
tifiques,"  zoth  February,  1867,  p.  78. 


CHAP.  I.]  SENSATIONS  OF  HEADING,  ETC.  JO7 

vibrations  is  of  certain  length,  and  lasts  a  certain  fraction  of  a 
second ;  that  the  more  it  diminishes  in  length  and  duration, 
the  more  acute  becomes  the  note.  All  analogies  show  that 
there  are  elementary  sensations  in  this  case, .just  as  in  that  of 
the  very  deep  note,  and  scientific  experiment  comes  in  to  con- 
firm these  inductions. — Take  a  wheel  with  two  thousand  teeth 
revolving  in  a  second  ;  it  gives  two  thousand  blows  in  a 
second,  and  therefore  two  blows  in  the  thousandth  part  of 
a  second ;  if  all  the  teeth  except  two  adjoining  ones  are  now 
removed,  the  two  blows  which  it  will  give  when  set  going 
again  will  only  occupy  the  thousandth  part  of  a  second.*  Now 
these  two  blows  cause  a  determinate  and  appreciable  sound. 
The  sound,  then,  given  in  a  second  by  the  wheel  when  it  has 
all  its  teeth,  comprises  a  thousand  similar  successive  sounds, 
each  perceptible  to  consciousness.  In  other  words,  the  whole 
sensation  which  lasts  a  second,  is  made  up  of  a  continuous 
series  of  a  thousand  similar  sensations,  each  lasting  one-thour 
sandth  part  of  a  second,  and  each  perceptible  to  consciousness. 
But  as  we  have  just  seen,  each  one  of  them  comprises  in  it- 
self at  least  two  successive  elementary  sensations,  which,  if 
isolated,  would  not  come  within  our  consciousness  and,  to  be  per- 
ceptible, must  be  combined  in  pairs.  Here  we  have  the  ele- 
ments of  a  sensation  lasting  a  second,  and  the  elements  of  its 
elements. 

Now,  in  the  passage  from  the  deep  to  the  acute  note,  what 
become  of  these  elementary  sensations  of  which  we  are  con- 
scious ?  It  is  plain  that  each  of  them  lasts  less  and  less  time 
and  that  its  maximum  sound  becomes  nearer  and  nearer  to 
the  maximum  of  the  succeeding  sound  ;  hence  it  will  necessa- 
rily become  less  and  less  distinct,  and  at  last  we  shall  cease  to 
perceive  any  maximum  or  minimum  in  it ;  this  is  what  hap- 
pens ;  in  proportion  as  the  note  becomes  acute,  the  number 
and  plurality  still  apparent,  though  indistinctly,  in  the  low  note, 
disappear  and  wholly  vanish.  Consciousness  no  longer  distin- 
guishes, even  vaguely,  the  little  composing  sensations ;  the 
whole  sound  appears  one  and  united. — At  the  same  time, 
it  puts  on  a  new  appearance,  it  seems  thinner  and  more  drawn 

*  Mueller  (tr.  Baly),  ii.  973  and  1298,  Experiments  of  Savart. 


104  OF  SENSATIONS.  [BOOK  III. 

out.  This  arises  from  the  closer  arrangement  of  the  maxima, 
and  from  the  shorter  time  occupied  by  the  molecules  of  the 
sensation,  which,  though  as  numerous  as  before,  are  smaller. 
It  follows  that,  as  regards  consciousness,  our  sensations  of 
sound  arrange  themselves  in  a  pyramid  :  at  the  base,  are  those 
of  very  deep  sound,  composed  of  longer  elementary  sensations 
and  more  distant  maxima  ;  at  the  summit,  are  those  of  very 
acute  sound,  composed  «of  shorter  elementary  sensations  and 
of  more  closely  ranged  maxima  ;  this  is  why  we  say  of  sounds 
that  some  are  higher  and  some  lower,  and  arrange  them  in  a 
scale. — Hence  we  see  that  the  qualities  of  deep  or  acute,  of 
high  or  low,  of  full  or  drawn  out,  of  vibrating  or  firm,  by  which 
we  distinguish  the  different  notes  of  the  scale,  depend  on  the 
degree  of  brevity  of  the  elementary  sensation,  and  the  degree 
of  proximity  of  its  maxima.  Here,  already,  we  have  reduced 
quality  to  quantity. 

IV.  It  is  also  thus  reducible  in  other  respects. — First,  as  to 
intensity,  the  reduction  is  complete.  The  different  degrees  of 
force  or  intensity  of  anyone  sensation  of  sound  are  the  different 
degrees  by  which  it  passes  from  its  minimum  to  its  maximum, 
and  we  know  that  these  degrees  have  as  their  necessary  and 
sufficient  condition  different  degrees  of  condensation  of  the 
wave  of  air.  Now,  mathematics  show  us  that  in  each  element- 
ary wave,  there  is  a  maximum  and  a  minimum  of  condensation, 
which  explains  how  it  is  we  find  in  each  elementary  sensation  a 
maximum  and  a  minimum  of  intensity.  Mathematics  further 
show  that  in  the  two  series  of  waves  produced  by  two  notes 
sounded  in  unison,  the  condensations  combine  and  become  of 
double  strength  ;  which  explains  how  it  is  that  in  the  sensa- 
tions of  sound  so  produced  the  intensities  combine  and  be- 
come doubly  as  great.  Consequently,  when  we  are  given  the 
law  connecting  the  elementary  sensation  with  its  condition, 
we  are  able  to  follow  the  elementary  sensation  under  all  its 
aspects  and  in  all  its  degrees,  far  above  the  range  of  con- 
sciousness, by  following  mathematically  the  changes  and  de- 
grees of  its  condition. 

In  the  second  place,  an  indirect  analysis  comes  to  our  aid 
to  explain  with  the  most  complete  success  that  undefinable 
quality  which  seemed  to  resist  all  the  efforts  of  direct  analysis, 


CHAP.  I.]  SENSATIONS  OF  HEARING,  ETC.  IO5 

tone.*  If  the  same  note  is  played  by  various  instruments  of 
different  tone,  it  is  not  a  simple  sound  but  a  combination  of 
sounds,  of  which  the  principal  one — the  same  for  all  the  instru- 
ments— is  the  fundamental  note  ;  and  the  others,  varying 
with  particular  instruments,  are  supplementary  notes  of  less 
strength,  termed  superior  harmonics,  arising  from  vibrations 
twice,  three,  four,  five,  six,  seven,  eight,  nine,  or  ten  times  as 
quick  as  those  of  the  fundamental  note,  Thus,  in  the  piano, 
we  can  hear  without  difficulty  the  six  first  harmonics  of  each 
note,  but  not  the  seventh  or  ninth.  The  violin,  under  the 
bow,  gives  the  six  first  harmonics  more  feebly ;  but  the  higher 
ones,  from  the  sixth  to  the  tenth,  are  very  distinct.  The  pipes 
of  covered  organs  give  a  hollow  sound,  arising  from  the  isola- 
tion of  the  odd  harmonics.  The  clarionet  gives  a  nasal  sound, 
in  which  again  there  are  only  the  odd  harmonics  ;  but  of  these, 
the  higher  ones  predominate.  Hence  it  follows  that  differences 
of  tone  arise  from  the  addition  of  different  harmonics  to  the 
fundamental  note.  By  following  out  this  principle,  and  with 
the  aid  of  an  instrument  called  a  resonnateur,  it  has  been 
proved  that  this  same  circumstance  explains  the  different 
vowel-sounds  of  the  human  voice — that  is  to  say,  the  varia- 
tions which  the  same  note  presents,  when  pronounced  in  turn 
u,  a,  e,  i,  o,  eu,  ou.  Analogous  considerations  shows  us  how 
sounds  become  either  harsh  and  rough,  or  smooth  and  even. 
So  that  these  differences  of  sensation  hitherto  irreducible,  and 
denoted  by  idle  metaphors,  are  reduced  to  the  intervention  of 
little  subsidiary  and  complementary  sensations  of  the  same 
kind,  which,  attaching  themselves  to  the  principal  sensation, 
give  it  a  special  character  and  unique  appearance,  while  con- 
sciousness, which  sees  the  whole  and  nothing  but  the  whole, 
is  unable  to  distinguish  these  feeble  auxiliaries,  and  there- 
fore to  recognize  that,  though  inferior  in  strength  to  the  prin- 
cipal sensation,  they  are,  in  nature,  identical  with  it,  and  that, 
while  entirely  similar  to  one  another,  they  differ  only,  accord- 
ing to  the  tone,  in  number  and  acuteness. 

This  being  settled,  we  are  in  a  position  to  explain  sensa- 
tions of  noise,  and  their  innumerable  varieties.     The  science 


Helmholtz,  "  Die  Lehre  von  den  Tonempfindungen." 


106  OF  SENSATIONS.  [BOOK  III. 

of  acoustics  shows  us  their  general  mode  of  formation,  though 
without  entering  into  the  details  of  each  particular  one.  Like 
sensations  of  musical  sounds,  they  are  compound.  But  while 
the  sensation  of  musical  sound  corresponds  to  a  series  of 
vibrations,  equal  in  length  and  duration,  that  of  noise  corre- 
sponds to  a  series  of  vibrations,  unequal  in  duration  and  length ; 
and  hence  we  conclude  that  in  the  first  instance  the  elementary 
sensations  are  similar,  and  in  the  second  dissimilar  ;  and  this 
explains  the  infinite  number  of  sensations  of  noise  and  the  im- 
possibility of  grouping  them  Ifke  those  of  musical  sound  in  a 
single  series ;  there  are  no  limits  to  the  combinations  of  dis- 
similar sounds  ;  having  no  fixed  relations  between  themselves, 
they  can  only  produce  a  chaos. 

We  see  now  in  what  all  the  differences  and  peculiarities  of 
sounds  consist.  Given  two  continuous  elementary  sensations, 
the  one  preceding  and  the  other  following,  the  two  united 
form,  as  far  as  consciousness  is  concerned,  a  single  whole  sen- 
sation, which  we  term  a  sensation  of  sound. — If  the  two  are 
similar,  the  sound  is  musical ;  if  they  are  dissimilar,  it  is  a 
noise. — If,  in  the  couple  so  formed,  the  elements  are  of  longer 
duration,  the  sound  is  deeper  ;  if  of  shorter  duration,  the  sound 
is  more  acute. — In  every  elementary  sensation,  there  is  a 
maximum  ;  and  according  as  the  time  between  two  maxima 
diminishes,  the  sound  becomes  more  even. — If  the  maxima  of 
one  couple  are  greater  than  those  of  another,  the  whole  sound 
of  the  first  couple  is  more  intense  than  the  whole  sound  of  the 
second. — If  to  the  whole  sound  be  added  complementary 
sounds,  less  intense,  and  twice,  three,  four,  or  several  times 
as  acute,  the  tone  varies  with  the  variations  of  the  comple- 
mentaries. — If  we  conceive  two  given  elements,  on  the  one 
hand,  the  elementary  sensation,  on  the  other,  the  quantity 
we  call  time ;  we  have  in  them  the  materials  necessary  to  con- 
struct sensations  of  sound. — Two  elementary  sensations  are 
discontinuous,  or  continuous,  that  is  to  say,  are  separated  by 
an  appreciable  or  unappreciable  portion  of  this  quantity ;  and 
the  sound  is  accordingly  null  or  appreciable. — They  occupy 
equal  or  unequal  portions  of  this  quantity ;  and  the  sound  is 
accordingly  musical  or  not  musical. — The  portions  so  occu- 
pied are  larger  or  smaller ;  and  the  sound  accordingly  becomes 


CHAP.  I.]  SENSATIONS  OF  HEARING,  ETC.  IO7 

deeper  or  higher. — If  we  now  conceive  the  magnitude  or  in- 
tensity of  the  elementary  sensation  itself,  with  this  new  ele- 
ment, the  construction  is  accomplished. — The  elementary  sen- 
sation having  a  maximum  of  intensity,  the  maxima  of  two 
elementary  sensations  may  be  discontinuous  or  continuous, 
that  is  to  say,  separated  by  an  appreciable  portion  of  time 
or  not ;  and  the  sensation  is  accordingly  composed  of  ap- 
preciable portions,  or  uniform. — The  maxima  of  two  •elemen- 
tary sensations  are  greater  or  less  than  the  maxima  of  two 
others  ;  and  the  sound  is  accordingly  more  or  less  intense. — 
There  are  added  to  a  sound  different  groups  of  sounds  of  less 
intensity,  but  of  an  acuteness  the  multiple  of  its  own ;  and 
the  sound  has  such-and-such  a  tone  accordingly.  So  that  all 
differences  of  sound,  though  apparently  irreducible,  are  re- 
duced to  differences  of  magnitude  introduced  into  the  same 
elementary  sensation,  these  differences  being  furnished  some- 
times by  the  magnitude  or  intensity  of  the  sensation  itself, 
sometimes  by  that  particular  magnitude  we  denominate  time. 
Let  us  now  consider  the  elementary  sensation  itself.  In 
the  noise  which  precedes  the  musical  note,*  it  is  united  with 
other  elementary  sensations  of  unequal  duration,  and  forms 
with  them  a  heterogeneous  compound.  In  the  musical  note 
which  is  formed  by  accelerated  and  approximating  noises,  it 
is  united  with  other  elementary  sensations,  of  duration  equal 
to  its  own,  and  forms  with  them  a  homogeneous  compound. 
But  for  it  to  reach  our  consciousness  there  must  always  be 
one  or  other  of  these  combinations ;  it  must  be  enlarged  in 
order  to  be  distinguished.  When  isolated,  the  inner  sense 
does  not  perceive  it ;  but  it  still  exists,  for  in  the  very  deep 
musical  note  we  perceive  it  incessantly  repeated  and  making 
up  the  note ;  and  again,  there  can  clearly  be  no  compound 
without  components. — On  the  other  hand,  we  have  seen  that 
in  the  high  as  in  the  low  note,  the  elementary  sensation  has  a 
maximum ;  we  discover  this  maximum  in  the  very  low  note, 
we  do  not  discover  it  in  the  high  note ;  still  it  exists  in  the 
one  as  in  the  other ;  but,  in  the  very  low  note,  the  greater 
interval  between  the  two  maxima  enables  us  to  distinguish 


*  See  the  Wheel  of  Savart,  and  the  Sirens. 


I0g  OF  SENSATIONS.  [BOOK  III. 

them,  while,  in  the  high  note,  their  proximity  prevents  our 
doing  so.— Further  than  this,  every  elementary  sensation,  in 
order  to  pass  from  its  minimum  to  its  maximum,  passes  in 
its  short  duration  through  an  infinite  number  of  degrees  ; 
much  more  therefore  are  these  degrees  insensible  to  con- 
sciousness; so  that,  in  a  high  note,  the  indistinct  elementary 
sensation  comprehends  not  only  two  indistinct  extreme  states, 
but  an  infinite  number  of  indistinct  intermediate  states. 

We  get  a  glance  here  at  the  obscure  and  infinite  world 
extending  beneath  our  distinct  sensations.  These  are  com- 
pounds and  wholes.  For  their  elements  to  be  perceptible  to 
consciousness,  it  is  necessary  for  them  to  be  added  together, 
and  so  to  acquire  a  certain  bulk,  and  to  occupy  a  certain  time ; 
if  their  group  does  not  attain  this  bulk  and  does  not  last  this 
time,  we  observe  no  change  in  our  state.  Nevertheless,  though 
it  escapes  us,  there  is  one ;  our  internal  sight  has  limits  ;  outside 
these  limits,  internal  events,  though  real,  are  for  us  as  though 
they  did  not  exist.  They  gain  accessions,  they  undergo  dim- 
inutions, they  combine,  they  are  decomposed,  without  our 
being  conscious  of  it.*  They  may  even,  as  we  have  just  seen 
in  the  case  of  sensations  of  sound,  have  different  degrees  of 
composition,  and  consequently  different  degrees  of  recoil,  be- 
yond the  grasp  of  consciousness.  The  elementary  sensations 
directly  making  up  our  ordinary  sensations  are  themselves 
compounded  of  sensations  of  less  intensity  and  duration,  and 
so  on.  Thus,  there  is  going  on  within  us  a  subterranean  pro- 
cess of  infinite  extent,  its  products  alone  are  known  to  us  and  are 
only  known  to  us  in  the  mass.  As  to  elements  and  their  ele- 
ments, consciousness  does  not  attain  to  them,  reasoning  con- 


*  Leibnitz,  "  Des  Perceptions  Insensibles,"  p  65,  "  Nouveaux  Essais  sur 
1'Entendement, "  Ed.  Jacques. 

"To  hear  the  sound  of  the  sea,  from  the  shore,  we  must  necessarily  hear  the  parts 
which  make  up  the  whole,  that  is  to  say,  the  noise  of  each  wave,  though  each  of 
these  little  noises  only  makes  itself  known  to  us  in  the  confused  assemblage  of  the 
whole,  and  wonld  not  be  observed  if  the  wave  causing  it  were  alone  by  itself.  For 
we  must  be  affected  a  little  by  the  movement  of  this  wave,  and  must  have  some 
perception  of  its  sound,  however  slight ;  otherwise  we  should  have  none  of  the 
sound  of  a  hundred  thousand  such,  since  a  hundred  thousand  nothings  cannot 
make  up  any  thing." — Cf.  Hamilton,  Lectures,  etc.,  i.  349-351,  cited  Mervoyer, 
"  De  1'Association  des  Idees,"  p.  337.  » 


CHAP.  I.J  SENSATIONS  OF  HEARING,  ETC.  IOQ 

eludes  that  they  exist ;  they  are  to  sensations  what  secondary 
molecules  and  primitive  atoms  are  to  bodies ;  we  have  but  an 
abstract  conception  of  them,  and  what  represents  them  to  us 
is  not  an  image,  but  a  notation. 


HO  OF  SENSATIONS.  [BOOK  III 


CHAPTER  II. 

SENSATIONS  OF  SIGHT,  OF  SMELL,  OF  TASTE,  OF  TOUCH,  AND 
THEIR  ELEMENTS. 

I.  A  SIMILAR,  though  somewhat  less  complete,  reduction 
may  be  effected  with  sensations  of  sight.*  We  all  know  that 
a  ray  of  white  light  may  be  divided  with  a  prism  into  several 
rays  of  different  colors.  It  spreads  out  into  a  spectrum,  in 
which  the  colors  form  a  continuous  scale.  At  the  commence- 
ment of  the  scale  is  red  ;  then  come  orange  and  the  different 
yellows,  then  green,  the  different  blues,  indigo,  and  lastly  vio- 
let,f  and  each  of  these  tints  passes  by  intermediate  stages  into 
the  one  preceding  it  and  the  one  following  it. — Here  are  an 
infinite  number  of  distinct  sensations  connected  by  inter- 
mediate stages.  Let  us  examine  their  external  conditions. 
The  science  of  optics  shows  us  that  the  spectrum  is  formed 
by  the  different  rays  which  make  up  the  white  ray  being  in- 
flected, some  more  and  some  less,  in  passing  through  the 
prism ;  this  inflection  increases  with  the  shortness  and  rapidity 
of  the  waves  ;  therefore,  if  we  follow,  from  red  to  violet,  the 
series  of  rays  which  form  the  spectrum,  we  find  that  the  short- 
ening and  acceleration  of  the  waves  go  on  increasing.  Thus, 
from  red  to  violet,  each  sensation  corresponds  to  waves  quicker 
and  shorter  than  those  of  the  preceding  sensation,  slower  and 
longer  than  those  of  the  succeeding  sensation.  An  increase 
of  speed  and  diminution  of  length  in  the  waves  are  sufficient 
r  to  determine  the  variations  which  our  sensation  of  color  un- 
goes  in  passing  from  red  to  violet. 

Having  premised  this,  let  us  consider  the  red ;  as  we  go 

*  Helmholtz,  "  Physiologische  Optik,"  part  ii. 

f  M.  Helmholtz  distinguishes  the  following  successive  colors :  red,  orange, 
golden  yellow,  pure  yellow,  greenish-yellow,  pure  green,  bluish-green,  blue  of  wa- 
ter, cyanic  blue,  indigo,  violet  and  ultra-violet. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  ni 

down  the  spectrum,  the  sensation  of  red  diminishes,  it  passes 
from  its  maximum  to  its  minimum.  There  is  then  an  elemen- 
tary sensation,  which  decreases  in  proportion  as  the  waves  be- 
come "shorter  and  more  rapid. — But  there  is  more  than  one 
such ;  for  if  there  were  only  one,  we  should  find  that  as  we 
passed  towards  violet,  it  would  simply  grow  feebler  with  the 
shortening  and  acceleration  of  the  waves,  and  the  entire  spec- 
trum would  only  present  degrees  of  intensity  of  red,  while  in 
fact,  we  find  at  what  appears  to  be  the  minimum  of  red,  a  second 
distinct  sensation  arising,  that  of  yellow.  There  are  then, 
at  least  two  elementary  sensations  of  color. — Are  there  but 
two?  If  there  were  only  two,  for  instance,  that  of  red  and 
that  of  yellow,  the  red,  having  its  maximum  at  the  commence- 
ment of  the  spectrum,  and  the  yellow  having  its  maximum  at 
the  centre  of  yellow,  the  first  decreasing  with  the  time  and 
length  of  the  waves,  the  second  decreasing  whenever  the  time 
and  length  of  the  waves  are  less  or  greater  than  the  degree 
of  time  and  length  corresponding  to  the  centre  of  yellow,  we 
should  see,  on  passing  down  the  spectrum  below  this  centre, 
yellow  become  indefinitely  feebler  till  the  end  of  the  spectrum, 
without  undergoing  any  other  change.  This  is  not  so ;  for 
at  the  lower  minimum  of  yellow  we  find  a  new  distinct  sensa- 
tion appear,  that  of  green. — There  are  then,  at  least  three 
elementary  sensations,  and  on  studying  the  composition  of 
the  spectrum  we  find  it  is  sufficient  to  admit  three,  one  analo- 
gous to  that  of  red,  another  to  that  of  violet,  and  the  last  to 
that  of  green. 

All  the  three  are  excited  by  every  ray  of  the  spectrum ; 
but  each  of  the  three  is  differently  excited  by  the  same  ray. 
— The  first  is  at  its  maximum  at  about  the  central  point  of 
red  ;  in  proportion  as  we  descend  towards  the  violet  and  the 
waves  become  shorter  and  more  rapid,  its  intensity  diminishes 
and  approaches  its  minimum. — The  second  is  at  its  maximum 
at  about  the  centre  of  the  violet ;  and  as  we  go  back  towards 
the  red,  and  its  waves  become  longer  and  slower,  its  intensity 
diminishes  and  approaches  its  minimum. — The  third  is  at  its 
maximum  at  about  the  central  point  of  the  green ;  in  pro- 
portion as  we  return  towards  the  red,  or  descend  towards  the 
violet,  that  is  to  say,  as  the  waves  become  either  longer  and 


112  OF  SENSATIONS.  [BOOK  III. 

slower,  or  shorter  and  more  rapid,  its  intensity  diminishes  and 
approaches  a  minimum. — So  that,  as  we  pass  from  red  to 
violet  through  all  the  degrees  of  the  spectrum,  the  three  com- 
ponent sensations  vary  from  degree  to  degree,  but  each  one 
in  a  special  manner,  the  first  passing  insensibly  from  maxi- 
mum to  minimum,  the  second  from  minimum  to  maximum, 
the  third  passing  first  from  a  minimum  to  its  maximum,  and 
then  from  its  maximum  to  a  minimum,  which  explains  at  the 
same  time  the  insensible  passage  by  which  every  compound 
sensation  in  the  spectrum  is  connected  with  the  succeeding 
one,  and  the  diversities  of  the  ten  or  twelve  principal  com- 
pound sensations.* 

We  can  readily  see  the  object  of  this  disposition  of  our  be- 
ing. If  a  simple  ray  excised  in  us  one  sensation  of  color  only, 
it  \vould  have  a  maximum,  a  minimum,  and  intermediate 
stages,  nothing  more  ;  and  for  want  of  being  able  to  contrast 
it  with  another,  we  should  not  observe  it  ;f  we  should  have 
no  notion  of  color;  the  luminous  waves,  in  increasing  or  de- 
crdasing  in  speed  and  length,  would  only  render  the  sensation 
more  intense  or  more  feeble  ;  objects  would  differ  only  in  high- 
er or  fainter  color ;  they  would  resemble  the  various  parts  of 
a  drawing  in  which  all  the  differences  are  those  of  white,  gray, 
and  black. — If,  on  the  other  hand,  every  simple  ray  excited 
two  sensations  of  color  only,  we  should  still  have  the  notion 


*  Helmholtz,  ib.,  191.  The  substance  of  this  explanation  is  due  to  Young. 
He  supposes  that  every  nervous  fibre  of  the  retina  is  made  up  of  three  elementary 
fibres,  differently  excitable  by  the  same  ray.  As  Helmholtz  observes,  we  may  sup- 
pose that  every  nervous  fibre  of  the  retina  possesses  three  different  kinds  of  activity, 
excitable  by  the  same  ray,  and  this  is  very  probable. — But  we  may  dispense  with 
all  suppositions  by  admitting,  instead  of  three  nervous  fibres  or  three  nervous  activ- 
ities, three  elementary  sensations.  In  the  anatomical  or  physiological  hypothesis, 
the  assumed  fact  is  uncertain  ;  for  it  is  not  certain  that  there  are  three  different 
fibres  in  every  nerve,  or  that  one  fibre  has  three  kinds  of  action.  In  the  psycho- 
logical explanation,  the  admitted  fact  is  positive  ;  for  it  is  certain  that  the  three 
sensations,  red,  green,  and  violet,  exist. — I  have  therefore  made  the  necessary 
changes  in  the  explanation  of  Helmholtz.  "  This  hypothesis  of  Young's,"  he  says, 
gives  a  complete  view  and  extraordinarily  clear  and  simple  explanation  of  all  the 
phenomena  connected  with  the  physiological  science  of  colors." 

f  "  Persons  affected  with  achromatopsy  can  only  distinguish  degrees  of  light 
and  dark,  they  see  all  objects  as  they  are  represented  in  photography." — Wecker, 
"  Maladies  des  Yeux,"  ii.  432. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  ll^ 

of  color  ;  we  should  still  distinguish  two  principal  colors,  their 
maxima,  minima,  intermediates  and  compounds ;  but  very 
many  of  our  sensations  of  color  would  be  wanting,  and  their 
whole  arrangement  would  be  reversed. — This  we  observe  in 
studying  various  cases  of  illness  or  congenital  infirmity,  and 
the  theory  reducing  our  elementary  sensations  of  color  to  the 
three  sensations  of  red,  violet,  and  green,  receives  here  a  most 
striking  confirmation  from  experience.'55' — The  sensation  of  red 
is  wanting  in  some  persons ;  in  others,  that  of  green ;  after 
taking  santonine,  the  sensation  of  violet  is  lost  for  some  hours. 
In  all  these  cases,  not  only  is  a  principal  sensation  missing, 
but  many  others  are  altered,  and  both  losses  and  alterations 
are  precisely  those  which,  according  to  theory,  would  result 
from  the  absence  of  the  elementary  sensation. — Finally,  we 
obtain  a  more  delicate  and  definitive  verification.-)-  Accord- 
ing to  the  theory,  the  red  and  violet  of  the  spectrum  are,  even 
at  the  points  at  which  they  seem  most  intense,  compound  sen- 
sations ;  for,  to  the  elementary  sensation  which  is  then  at  its 
maximum,  are  joined  two  others  which  are  then  at  a  minimum ; 
the  first  then  is  mingled  and  weakened  ;  it  is  neither  absolute- 
ly pure  nor  of  the  greatest  possible  strength.  It  will,  then, 
be  purer  and  stronger  if  we  can  remove  these  causes  of  impu- 
rity and  weakness.  Now  there  is  a  case  in  which  we  are  able 
to  do  this ;  that  is,  when  we  have  blunted  the  sensibility  of 
the  eye  to  the  other  colors.  In  this  case  we  ought  to  see  a  red 
or  violet  more  intense  than  those  of  the  spectrum  ;  and  this 
is  what  happens.  In  this  instance,  which  is  unique,  we  are 
able  to  isolate  one  of  our  elementary  sensations  of  color.  By 
a  lucky  hit  in  psychological  chemistry,  we  extract  it  from  the 
ternary  compound  in  which  it  is  usually  combined,  and  in  which 
theory  alone  had  detected  it. 


*  Helmholtz,  294,  848,  293,  and  Wecker,  ibid. — "The  ingestion  of  santonine 
brings  on  a  particular  variety  of  Daltonism  by  making  the  retina  insensible  to  vi- 
olet rays.  .  .  ."  Some  persons  "  have  no  perception  of  blue ;  this  state  always 
coincides  with  insensibility  of  the  retina  to  red  rays.  '  Others  while  distinguishing 
white,  gray,  and  black  from  all  other  colors,  do  not  distinguish  other  colors, 
from  one  another.  In  others,  the  retina  is  insensible  to  violet,  while  other  colors 
are  perceived,  if  strongly  marked  and  in  a  bright  light" 

f  Helmholtz,  ib.,  369,  370. 

8 


OF  SENSA  TIONS.  [BOOK  III. 

II.  With  the  three  elementary  sensations  of  color  we  are 
able  to  construct  the  rest.  And  first,  if  we  represent  by  a 
curve  the  increase  and  decrease  which  each  of  them  undergoes 
as  it  passes  down  the  spectrum,  we  shall  see  the  three  differ- 
ent variations  of  their  respective  intensities  produce  the  differ- 
ent colors  of  the  spectrum.* — The  longest  and  slowest  waves, 
placed  at  the  summit  of  the  spectrum,  excite  the  elementary 
sensation  of  red  strongly,  and  the  two  others  feebly ;  the  re- 
sult is  the  sensation  of  spectral  red. — Lower  down,  at  the 
point  denoted  by  yellow,  the  waves,  already  not  so  long  and 
slow,  excite  the  elementary  sensations  of  red  and  green  with 
moderate  intensity;  and  that  of  violet  feebly;  and  then  we 
have  the  sensation  of  spectral  yellow. — Towards  the  middle 
of  the  spectrum,  the  waves,  which  then  have  a  medium  length 
and  speed,  excite  the  elementary  sensation  of  green  strongly, 
and  the  others  much  more  feebly ;  our  entire  sensation  is  that 
of  spectral  green. — Lower  down,  when  the  waves  begin  to 
grow  short  and  quick,  the  elementary  sensations  of  violet  and 
green  are  excited  with  moderate  force,  and  that  of  red  more 
feebly  ;  then  we  see  spectral  blue. — Towards  the  lowest  part, 
when  the  acceleration  and  shortening  of  the  waves  has  fur- 
ther increased,  the  elementary  sensation  of  violet  is  strong,  and 
those  of  red  and  green  are  very  weak  ;  and  the  compound  sen- 
sation we  call  violet  is  produced. 

On  the  other  hand,  when  the  three  elementary  sensations 
are  of  about  equal  force  and  no  one  predominates  over  the 
others,  we  have  the  sensation  of  white,  or  of  whitish  colors. 
This  happens  in  many  cases ;  first,  when  all  the  rays  of  the 
spectrum,  collected  again  by  another  prism,  strike  the  retina 
at  the  same  point,  and  thus  produce  the  maximum,  minimum, 
and  all  the  degrees  of  each  elementary  sensation ;  again 
when,  two  rays  being  selected  from  the  spectrum,  the  inequal- 
ity of  the  three  elementary  sensations  excited  by  the  first  is 
compensated  by  the  inverse  inequality  of  the  three  elementa- 
ry sensations  excited  by  the  second.  In  this  case,  the  two 
spectral  colors  produced  by  the  two  rays  are  said  to  be  com- 
plementary to  one  another,  and  they  form  a  distinct  couple. 

*  Helmholtz,  291. 


CHAP  II.]  SENSATIONS  OF  SIGHT,  ETC.  jje 

Among  such  couples  we  reckon  four  principal  ones,  red  and 
bluish-green,  orange  and  cyanic  blue,  yellow  and  indigo, 
greenish-yellow  and  violet ;  combined  in  their  respective  pairs, 
these  colors  give  us  the  sensation  of  white,  and  we  find  a  fix- 
ed distance  between  such  pairs  on  the  spectrum. — If,  on  the 
contrary,  we  take  the  two  colors  at  the  furthest  distance  from 
one  another  on  the  spectrum,  red  and  violet,  their  mixture 
produces  a  sensation  of  distinct  color,  that  of  purple. — These 
two  observations  afford  us  the  law  governing  all  mixtures  of 
spectral  colors. — Two  colors  being  given  for  mixture,  their 
distance  on  the  spectrum,  compared  with  the  fixed  distance 
between  complementary  colors,  differs  from  it  by  a  greater  or 
less  quantity.  The  smaller  this  quantity  is,  the  nearer  to 
white  or  whitish  will  be  the  color  produced  by  the  mixture  ; 
and  on  the  contrary,  the  greater  this  quantity  is,  the  freer 
from  white,  or  more  "  saturated,"  will  the  color  formed  by  the 
mixture  be. — On  the  other  hand,  this  distance  may  exceed 
or  be  less  than  the  fixed  distance.  The  more  it  exceeds  the 
fixed  distance  and  the  nearer  it  approaches  to  the  extreme 
possible  distance,  the  nearer  will  the  color  formed  by  the  mix- 
ture approximate  to  purple,  which  is  produced  when  the  sep- 
aration is  most  complete ;  on  the  contrary,  the  further  it  is 
below  the  fixed  distance  and  the  smaller  the  separation  be- 
comes, the  more  does  the  color  produced  approximate  to  the 
intermediate  color,  in  which  the  separation  of  the  two  compo- 
nent spectral  colors  disappears.*  All  these  conclusions  are 
confirmed  by  experience. 

A  last  color  remains,  black,  which  is  not  a  sensation,  but 
the  absence  of  all  sensation  at  a  particular  place  and  moment, 
when  this  place  and  moment  are  compared  with  others  in  which 
the  sensation  is  present.  But  consciousness  is  so  ill-acquaint- 
ed with  our  internal  events  that  she  places  in  the  same  rank, 
as  colors,  our  sensations  and  our  wants  of  sensation ;  what 
strike  her  are  differences  between  our  states,  and,  on  account 
of  this,  she  sets  together  as  similar  facts  the  passage  from  re- 
pose to  action,  and  that  from  action  to  repose,  observing  them 
as  contrary,  but  without  distinguishing  that  one  is  negative, 


*  Helmholtz,  279. 


IT6  OF  SENSATIONS.  [BOOK  III. 

the  other  positive.  The  different  degrees  of  black  or  of  want 
of  sensation  come  in  then  to  complicate  the  colors  already 
constructed.  "  Prismatic  analysis  proves  that  gray  becomes 
identical  with  white,  brown  with  yellow,  reddish  brown  with 
red,  olive  green  with  green,  when  the  white,  yellow,  red,  and 
green  are  feebly  luminous." 

These  data  being  given,  we  have  all  the  elements  neces- 
sary to  explain  all  sensations  of  color,  and  we  see  the  elements 
of  the  sensation  form  compounds,  which  combining  together 
form  more  complex  compounds,  and  so  on,  just  as  we  see 
physical  atoms  form  chemical  molecules,  these  form  chemical 
compounds,  and  these  again,  the  ordinary  minerals  found  in 
nature. — By  our  utmost  analysis  we  arrive  at  three  elementa- 
ry colors,  all  simultaneously  excited,  though  each  one  differ- 
ently, by  a  simple  ray  of  the  prism.  Their  union  forms  a 
spectral  color. — Many  spectral  colors  united  form,  in  accord- 
ance with  a  fixed  law,  white,  purple,  and  an  infinite  number 
of  compound  colors  ;  and  the  addition  of  black,  that  is  to  say, 
the  enfeebling  the  whole  sensation,  introduces  an  infinity  of 
shades  in  all  these  products. — These  products  themselves 
form,  by  their  combinations,  the  ordinary  colors  we  observe 
in  the  world  surrounding  us. 

Positive  science  stops  here  ;  experience  does  not  enable 
us  to  mount  higher  than  the  three  elementary  sensations  of 
color.  We  are  dealing  with  an  instrument  far  more  compli- 
cated than  the  sensation  of  hearing.  In  fact,  for  every  undu- 
lation we  have  three  sensations  instead  of  one.  With  sound 
again,  the  vibrations  sometimes  succeed  one  another  slowly 
enough  to  enable  us  to  distinguish  the  elementary  sensation 
corresponding  to  each  of  them  ;  there  are  only  sixteen  and  a 
half  per  second  in  the  ut  of  an  organ-pipe  thirty-two  feet  long ; 
and  so  we  are  able  to  observe  that  our  whole  sensation  is  made 
up  of  successive  small  sensations  having  each  a  maximum  and 
minimum;  we  distinguish  almost  precisely  these  component 
sensations.  With  sight,  on  the  contrary,  at  the  extremity  of 
red,  the  part  of  the  spectrum  where  the  vibrations  succeed  most 
slowly,*  there  are  451  billions  of  them  in  a  second ;  it  is  plain 

*  Mueller  (tr.  Baly),  ii.  1109,  and  Helmholtz,  p.  32. — 451  billions  for  the 
slowest,  789  billions  in  the  quickest. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  nj 

that,  were  we  able  to  isolate  the  sensation  of  red  from  the 
two  other  elementary  sensations,  we  could  never  distinguish 
from  one  another  component  sensations  so  prodigiously  nu- 
merous and  of  so  prodigiously  short  duration.  All  we  can 
admit  with  confidence  is  that  the  elementary  sensation  of  red, 
like  that  of  the  lowest  note  of  ut,  is  composed  of  successive 
sensations.  For  Wheatstone's  experiments  show  that  such 
a  light  as  that  of  the  electric  spark  is  enough  to  produce  a 
sensation  on  the  retina ;  that  this  light  is,  so  to  speak,  instan- 
taneous ;  that  it  lasts  less  than  the  millionth  of  a  second  ;  and 
that  thus  a  sensation  of  light  lasting  a  second  is  made  up  of 
at  least  a  million  successive  sensations.  The  number  of  these 
cannot  be  determined  ;  it  is  probably  much  greater ;  perhaps 
with  the  ethereal  undulation,  as  with  the  undulation  of  air, 
two  successive  vibrations  are  sufficient  to  produce  a  sensation 
still  perceptible  to  consciousness  ;  if  so,  the  shortest  sensation 
of  light  perceptible  to  consciousness  would — as  is  the  case 
with  the  shortest  sensation  of  hearing  perceptible  to  con- 
sciousness— be  compounded  of  two  elementary  sensations 
imperceptible  to  consciousness,  and  having  each  a  maximum 
or  minimum  and  intermediate  stages. — Without  pushing  the 
induction  to  this  extent,  the  case  of  the  electric  spark  shows 
that  the  sensation  of  light,  like  that  of  a  very  acute  sound,  is 
composed  of  a  continuous  succession  of  very  numerous,  suc- 
cessive, and  similar  sensations,  forming,  as  far  as  we  are  con- 
cerned, a  simple  undecomposable  mass.  A  new  proof  of  the 
unnoticed  work  going  on  in  the  depth  of  our  being,  beyond 
the  range  of  our  consciousness,  and  a  new  example  of  the 
latent,  complex,  and  innumerable  combinations,  of  which  we 
only  perceive  the  totals  or  the  effects. 

III.  We  must  not  expect  to  find  such  complete  reductions 
in  the  cases  of  taste  and  smell.  With  air,  or  ether,  we  know 
the  mode  of  action,  which  is  an  undulation  of  calculable  length 
and  speed,  and  thus  we  are  able  to  draw  conclusions  from  it 
to  the  corresponding  sensations.  Besides,  this  mode  of  action 
is  uniform,  and  the  nerve,  moreover,  is  specially  constructed 
to  receive  it ;  we  find  proof  of  this  in  the  designed  structure  of 
the  organism  of  which  the  nerve  forms  part,  and  in  the  simil- 
itude of  the  sensations  produced  through  the  nerve  by  a  blow 


Ug  OF  SENSATIONS.  [BooK  III. 

or  an  electric  current  applied  to  the  eye  or  ear.  The  nerve 
itself,  then,  is  capable  of  uniform  action ;  and  so  it  is  natural 
that  sensations  excited  by  its  action  should  be  readily  referable 
to  a  simple  type,  as  happens  with  those  of  sound,  or  to  types 
few  in  number,  as  with  those  of  color. — With  the  other  groups 
of  sensations  all  this  is  reversed.  We  are  ignorant  of  the  mode 
of  action  of  volatile  substances  on  the  olfactory  nerves  and  of 
liquefied  substances  on  the  gustatory  nerves  ;  it  is  recognized 
to  be  chemical,  but  here  our  knowledge  stops  ;  we  do  not  know 
whether  it  is  an  undulation  or  what  other  movement ;  we  have 
not  the  least  idea  of  its  elements,  and  are  unable  to  avail  our- 
selves of  such  an  idea  to  form  conclusions  as  to  the  corre- 
sponding sensations. — And  yet,  from  the  single  fact  that  it  is 
chemical,  we  may  conclude  something  as  to  the  composition 
of  the  sensations  it  exites  in  us  through  the  medium  of  the 
nerve. 

Before  commencing  this  inquiry,  we  must  distinguish  sen- 
sations of  smell  and  taste,  strictly  so  called,  from  accompanying 
sensations.  For,  what  we  term  a  smell  or  taste  is,  in  general, 
a  very  complex  sensation ;  the  olfactory  or  gustatory  nerves 
only  contribute  a  part  of  it ;  another  very  considerable  part 
referable  to  nerves  of  touch,  similar  to  those  spread  over  the 
rest  of  the  body,  and  from  which  we  receive  sensations  of 
contact,  of  muscular  contraction,  heat,  cold,  local  pains,  and 
all  their  kinds. — To  begin  with  smell.*  Numbers  of  what  are 
termed  sensations  of  smell  comprise  other  sensations.  And 
first,  sensations  of  pungent  smell  are  divisible  in  two  parts; 
they  all  comprise  sensations  of  touch  and,  perhaps,  are  nothing 
more ;  such  is  the  smell  of  ammonia,  which  is  principally  a 
stinging,  as  it  is  transmitted  by  other  nerves  than  the  special 
ones;  the  vapor  of  ammonia  produces  on  the  conjunctiva  an 
effect  precisely  similar  to  its  smell.  This  stinging  may  subsist 
even  after  the  strict  sensation  of  smell  has  been  lost ;  some 
great  snuff-takers  become  insensible  to  smells,  pleasant  or 
otherwise,  but  continue  to  take  snuff,  as  they  still  feel  the 
tingling  it  produces. — Appetizing  and  nauseating  smells  are 
also  thus  divisible.  The  strict  sensation  of  smell  is  here 


*  Bain,  "  Senses  and  Intellect,"  173. 


CHAP.  II.]  SENSATIONS  OF   SIGHT,    ETC. 

combined  with  another,  which,  according  to  the  state  of  the 
stomach,  ceases,  is  augmented,  or  reversed  ;  the  same  smell, 
that  of  a  plate  of  hot  meat,  is  agreeable  when  we  are  hungry, 
and  disagreeable  when  we  are  suffering  from  indigestion  ;  it  is 
probable  that,  in  this  case,  ceitain  deep-seated  nerves  of  the 
alimentary  canal  are  called  into  action,  and  that  the  whole 
sensation  is  made  up  of  a  sensation  of  the  olfactory  nerves  and 
several  accompanying  sensations. — Finally,  we  may  also  divide 
refreshing  and  suffocating  smells,  comprising,  on  the  one  hand 
those  of  the  volatile  salts  of  eau-de-Cologne,  of  tar,  of  tan ; 
and,  on  the  other  hand,  that  of  a  close  room,  of  a  pastry-cook's 
shop,  of  a  cotton  factory,  of  a  cloth  warehouse  ;  here  we  plain- 
ly have,  in  addition  to  the  strict  sensation  of  smell,  a  sensation 
of  comfort  or  uneasiness,  arising  from  the  air-passages,  and 
conducted  by  the  nerves  of  touch  and  pain. — I  think,  too,  that 
in  many  cases,  if,  for  instance,  we  inhale  alcohol,  a  feeble  sensa- 
tion of  heat  comes  in  to  complicate  the  strict  sensation  of 
smell. — Pure  sensations  of  smell  remain,  agreeable  or  disagree- 
able in  themselves ;  those,  for  instance,  of  the  violet  and  of 
assafcetida ;  there  are  an  infinite  number  of  them,  of  which 
we  can  only  say,  that  they  are  agreeable  or  disagreeable ;  in 
themselves,  they  resist  all  analysis,  and  in  order  to  denote  them 
we  have  to  name  the  bodies  producing  them. 

As  to  taste,  what  we  generally  term  a  flavor,  comprises, 
besides  the  strict  sensation  of  taste,  a  number  of  sensations 
of  other  kinds. — In  the  first  place,  as  the  back  of  the  mouth 
and  nose  communicate,  the  olfactory  nerve  is  in  operation  at 
the  same  time  as  the  gustatory.*  "  If  you  close  your  eyes 
and  nostrils,  and  have  different  kinds  of  sweetmeats,  for  in- 
stance, placed  on  your  tongue,  then  aromatic  creams,  of 
vanilla,  of  coffee,  etc.,  in  every  case  you  will  only  perceive  a 
sweet,  sugared  taste,  and  will  not  be  able  to  distinguish  the 
different  substances  employed."  In  the  same  way  it  can  be 
proved  that  "  the  urinous  taste  we  attribute  to  fixed  alkaline 
bases,  does  not  belong  to  these  substances,  but  to  the  ammo- 
nia set  free  by  the  reaction  of  the  fixed  alkaline  bases  on  the 
ammoniacal  salts  contained  in  the  saliva."  Here,  again,  a 


*  Longet,  "  Traite  de  Physiologic,"  ii.  171.  Bain,  "  Senses  and  Intellect,"  157. 


I2Q  OF  SENSATIONS.  [BOOK  III. 

sensation  of  smell,  or  rather  of  nasal  touch,  is  included  in  the 
sensation  of  taste. — Secondly,  strict  sensations  of  taste  are 
frequently  combined  with  a  different  sensation,  sometimes 
agreeable  and  attractive,  sometimes  disagreeable  and  repulsive, 
belonging  to  other  nerves  of  the  alimentary  canal.  This  ac- 
companying sensation  varies,  while  the  others  remain  constant ; 
the  same  good  plate  of  meat  is  agreeable  or  disagreeable,  ac- 
cordingly as  the  stomach  is  empty  or  loaded.  Besides  this, 
it  arises  in  other  ways ;  it  has  no  need,  like  the  other,  of 
chemical  action  as  an  excitant ;  mere  contact  is  enough ;  a 
finger  or  a  feather  in  the  throat  will  produce  a  sensation  of 
disgust. — Thirdly,*  "  Many  impressions  referred  to  taste  are 
simply  tactile ;"  such,  for  instance,  are  acrid,  irritant,  astrin- 
gent flavors,  which  are  sensations  of  touch,  not  of  taste. — 
Fourthly,  certain  flavors  are  combined  with  sensations  of  heat 
and  cold ;  the  sensation  of  heat  accompanying  strong  drinks 
is  well  known,  and  also  the  cool  sensation  we  find  as  an  ele- 
ment in  the  flavor  of  certain  sweetmeats. — Lastly,  different 
sensations  are  excited  by  the  same  body  in  different  parts  of 
the  mouth,  and  not  only  different  accompanying  sensations, 
but  different  sensations  of  pure  taste.f  "  Numbers  of  bodies, 
and  particularly  the  salts,  exhibit  the  remarkable  peculiarity 
of  exciting,  when  applied  to  the  back  of  the  tongue,  an  entire- 
ly different  sensation  from  what  they  excite  when  applied  to 
the  anterior  part.  Thus,  the  solid  acetate  of  potash,  of  a 
burning  acidity  in  the  anterior  part  of  the  mouth,  becomes  in- 
sipid, bitter,  and  nauseating  at  the  back,  and  loses  entirely  its 
acid  pungent  taste.  Hydrochlorate  of  potash,  simply  salt  and 
fresh  in  the  anterior  part,  becomes  sweetish  at  the  back. 
Nitrate  of  potash,  fresh  and  pungent  in  front,  is  insipid  and 
slightly  bitter  at  the  back.  Alum  is  fresh,  acid,  and  astringent 
when  crushed  in  the  front  of  the  mouth,  while  behind  it  gives 
a  sweetish  taste  without  the  least  acidity.  Sulphate  of  soda 
is  distinctly  salt  in  front,  and  distinctly  bitter  behind."  Ace- 
tate of  lead,  fresh,  piquant,  and  astringent  in  front,  becomes 

*  Vernier,  cited  by  Longet,  "  Traite  d'Anatomie  et  de  Physiologic  du  Systeme 
Nerveux,"  ii.  170.  Bain,  ibid. 

f  Longet,  "  Traite  de  Physiologic,"  ii.  167.  "  Experiments  of  Guyot  and 
Admyrault." 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  12\ 

sweet  at  the  back. — Hence  it  follows  that  an  ordinary  sensa- 
tion of  taste  may  have  several  distinct  elements  in  itself,  in 
addition  to  the  four  kinds  of  elements  furnished  by  accom- 
panying sensations.  For,  in  addition  to  the  non-gustatory 
nerves,  there  are  different  gustatory  nerves  which  intervene 
to  produce  it.  The  mouth,  then,  is  not  a  simple  organ,  but 
a  succession  of  organs,  and  a  taste,  even  one  strictly  so  called, 
may  be  a  succession  of  tastes. 

Let  us  simplify  the  matter  ;  let  us  lay  aside  all  that  part 
of  the  sensation  which  may  be  referred  to  touch,  such  as 
acidity,  astringency,  irritation,  heat,  coolness,  the  spontaneous 
muscular  sensation  radiating  towards  the  alimentary  canal, 
and  consider  simply  the  sensations  of  the  gustatory  nerves 
themselves,  and  put  them  on  the  same  footing,  whether  they 
arise  in  the  anterior  part,  or  at  the  back  of  the  mouth  ;  their 
principal  types  are  the  sensations  of  bitter  and  sweet,  with 
their  innumerable  varieties  ;  when  we  have  thus  named  them, 
we  are  at  the  end  of  our  knowledge,  as  happened  just  now 
when  we  called  sensations  of  smell  fetid  or  perfumed. — Still, 
let  us  see  what  we  can  learn  in  either  case  by  availing  our- 
selves of  previous  reductions,  and  by  studying  the  circumstan- 
ces in  which  these  sensations  arise.  They  have,  like  the  rest, 
as  direct  stimulus,  an  action  of  the  nerve  transmitted  to  the 
nervous  centres.  Now  it  is  admitted,  in  accordance  with  all 
known  facts,  that  two  different  sensations  indicate  two  different 
states  of  the  nervous  centres,  and,  if  the  same  nerve  is  con- 
cerned, two  different  actions  of  that  nerve. — It  remains,  then, 
to  be  known  in  what  way  the  olfactory  or  gustatory  nerves 
act ;  and,  to  arrive  at  this,  we  must  determine  the  external 
event  in  immediate  sequence  to  which  its  action  commences. 
Nothing  is  easier  than  to  know  the  antecedents  of  this 
event ;  but  it  is  difficult  to  determine  accurately  the  event  it- 
self. We  see,  at  first  sight  and  by  ordinary  experience,  that 
such  a  body  excites  in  us  such  a  sensation  of  taste  or  smell, 
that  another  excites  in  us  the  sensation  of  red,  or  blue  ;  but 
neither  one  nor  the  other  excite  these  sensations  otherwise 
than  through  media ;  the  science  of  optics  was  required  to  tell 
us  that  undulations  of  an  ether  of  certain  length  and  speed  are 
the  media  of  action  of  the  second  :  and  it  would  be  necessary 


122  OF  SENSATIONS.  [BOOK  III. 

to  have  recourse  to  a  science  already  constructed  to  determine 
the  media  of  action  of  the  first. — Let  us  inquire,  however, 
into  this  last  immediate  event  in  direct  sequence  to  which  the 
olfactory  or  gustatory  nerves  begin  to  act.  A  body  has  no 
taste  unless  in  solution;  the  taste  is  increased  when  it  is 
moved  about  and  pressed  to  the  gustatory  membrane  ;*  this 
membrane,  again,  must  not  be  dry,  or  rendered  insensible  by 
cold.  Again,  the  gustatory  nerves  are  probably  protected 
by  a  colloid  membrane,  permeable,  as  are  all  such,  to  non-col- 
loid substances,  but  nearly  impermeable  to  colloid  substances, 
which  accounts  for  the  taste  of  non-colloid  substances,  and  the 
want  of  taste  in  colloid  ones.  All  these  facts  lead  us  to  the 
conclusion  that  the  dissolved  molecules  of  the  body  which  is 
tasted  penetrate  the  tissues  of  the  tongue,  and  come  in  con- 
tact with  the  nervous  papillae  ;  and  there,  under  the  influence 
of  the  animal  heat,  form  with  the  liquid  secretions  a  chemi- 
cal combination  varying  with  the  variations  of  these  secre- 
tions.f — Similarly,  a  body  has  no  smell,  except  in  a  gaseous 
state;  and  the  pituitary  membrane  must  not  be  dry;  it  is 
also  proved  that,  to  be  odorous,  a  gas  must  combine  with  oxy- 
gen at  the  surface  of  the  pituitary  membrane.  All  these 
facts  lead  to  one  and  the  same  conclusion,  that  the  molecules 
of  gas  become  absorbed  in  the  moisture  of  the  pituitary  mem- 
brane in  contact  with  the  olfactory  fibres,  and  there  form  a 
chemical  combination  with  the  oxygen  of  the  air. — Thus  the 
action  of  the  olfactory  nerve,  like  that  of  the  gustatory  nerves, 
appears  to  have  a  chemical  combination  as  its  immediate  ante- 
cedent. 

Now  what  is  a  chemical  combination?  Chemists  reply 
that  a  homogeneous  body  is  made  up  of  molecules  precisely 
similar  to  one  another,  and  extraordinarily  small ;  that  each 
of  them,  if  the  body  is  not  simple,  is  itself  composed  of  several 
different  atoms  much  smaller  still,  and  so  situated,  with  re- 


*  Bain,  "Senses  and  Intellect,"  156,  168. 

*  Longet,  ii.  164. — "  The  most  delicate  kinds  of  food  are  tasteless,  earthy  or 
bitter  when  the  stomach  is  out  of  order.  .  .  .  The  brain  and  sensorial  nerves  re- 
main as  they  were,  but  the  tongue  is  covered  with  a  mucous  or  bilious  coating,  and 
every  thing  produces  a  dull  nauseous  impression."  Mueller  (tr.  Baly),  ii.  1323. — 
"  After  chewing  the  root  of  the  sweet-flag,  milk  and  coffee  taste  acid  to  me." 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  12^ 

spect  to  each  other,  as  to  remain  in  equilibrium  ;  that  a  chemi- 
cal combination  takes  place  when  a  molecule,  receiving  an 
atom  of  another  kind,  passes  into  another  state  of  equilibrium; 
that  the  atoms  then  leave  their  respective  positions  to  take 
up  new  ones;  that  these  displacements  of  atoms,  acting  at 
extremely  small  distances,  are  themselves  extremely  small ; 
that,  as  these  atoms  are  wonderfully  small,  we  must,  to  explain 
their  active  force,  attribute  to  them,  on  displacement,  veloci- 
ties of  enormous  magnitude ;  and  that,  therefore,  every  dis- 
tinct chemical  combination  is  made  up  of  a  distinct  system  of 
prodigiously  small  and  rapid  displacements,  of  which  we  can- 
not yet  indicate  the  elements  or  explain  precisely  the  type.* 
Here  we  have  the  immediate  antecedent  of  the  action  of  each 
olfactory  or  gustatory  fibre  ;  and  we  cannot  help  observing 
how  closely  it  resembles  the  immediate  antecedent  of  the 
action  of  the  optic  nerve,  but  with  this  difference,  that  in  the 
second  case  the,  type  and  elements  of  the  antecedent  are 
known.  In  fact,  in  the  vibration  of  either,  the  active  particles 
are  also  of  extraordinary  minuteness  ;  their  displacements  are 
also  wonderfully  small  and  rapid  ;  they  form,  also,  a  number  of 
distinct  systems.  Only  we  know  that  these  systems  are  all 
made  up  of  waves,  and  we  can  measure  the  speed  and  length  of 
each  wave  ;  and  thus  we  are  able  to  define  exactly  the  element- 
ary displacement  by  whose  repetition  each  system  is  formed, 
to  show  that,  in  different  systems,  the  elementary  displace- 
ments differ  in  respect  of  quantity  only,  to  reduce  them  all  to  a 
single  type,  to  denote  the  corresponding  elementary  action  of 
the  optic  nerve  and  brain,  and  to  conclude  the  existence  of  an 
elementary  optical  sensation,  by  whose  prodigiously  rapid  and 
multiplied  repetitions  our  total  sensations  of  color  are  made  up. 
Unfortunately,  chemistry  is  not  so  far  advanced  as  optics  : 
it  can  only  prove  the  existence  of  systems  of  displacements, 
while  the  other  science  defines  and  measures  them ;  it  must 
wait  till,  like  its  rival,  it  can  represent  these  infinitely  small 
events,  of  which  it  only  knows  the  final  effect. — But  it  is  plain 


*  "  Chemistry  has  as  yet  been  constructed  with  reference  to  masses  only ;  its 
construction  with  reference  to  velocities  remains  to  be  accomplished." — Saigey, 
"  De  1'Unite  des  Forces  Physiques,"  p.  184. 


124  OF  SENSATIONS.  [BOOK  III. 

that  in  the  two  cases  the  problem  and  solution  are  of  similar 
nature.  In  each,  movements  are  dealt  with,  the  minuteness, 
speed,  and  number  of  which  are  wholly  disproportioned  to  the 
ordinary  magnitudes  we  are  capable  of  estimating  in  time  and 
space.  We  may  compare,  then,  the  wave  of  either  to  a  sys- 
tem of  atomic  movements,  and  a  succession  of  similar  waves 
of  either  to  a  succession  of  similar  systems  of  atomic  move- 
ments. Consequently,  thanks  to  the  first  case,  we  can,  to 
some  extent,  represent  to  ourselves  the  second. 

A  molecule  comes  in  contact  with  an  olfactory  fibre  or  a 
gustatory  papilla  ;  a  system  of  atomic  movements  takes  place 
in  the  molecule,  and  a  corresponding  action  follows  in  the 
fibre  ;  a  second  similar  molecule  arrives  at  the  same  point ;  a 
second  similar  system  of  atomic  movements  takes  place,  and 
a  second  exactly  similar  corresponding  action  follows  in  the 
same  fibre.  The  two  similar  nervous  actions  have  aroused  two 
similar  cerebral  actions,  and  two  similar  elementary  sensa- 
tions. But  the  number  of  such  sensations,  actions,  and  systems 
of  movements  succeeding  in  a  second  is  enormous,  and  the 
whole  sensation  of  smell  or  taste,  like  the  whole  sensation  of 
color,  is  but  the  sum  of  all  the  successive  elementary  sensa- 
tions, the  series  of  which  occupies  a  certain  time.* 

We  can  now  form  an  idea  of.  the  four  special  senses.  The 
distinctive  character  of  their  sensations  is  that  each,  even  the 
simplest,  of  those  we  are  conscious  of,  is  made  up  of  a  succes- 
sion of  very  numerous  elementary  sensations  of  extremely 
small  duration,  whose  rhythm  corresponds  to  the  special 
rhythm  of  an  external  event,  to  an  undulation  of  air  or  ether, 
to  a  system  of  atomic  movements,  forming  the  external  nat- 
ural antecedent  with  regard  to  which  the  sense  was  construct- 
ed, and  by  the  presence  of  which  it  ordinarily  acts. — What 


*  Certain  points  of  agreement  show  us  the  connection  of  our  sensations  of 
smell  and  taste  with  the  atomic  constitution,  and  therefore  with  the  change  of 
atomic  constitution  of  the  molecules  (Bain,  152, 165).  Three  atoms  of  oxygen  with 
two  atoms  of  a  metal  form  a  compound  of  sweet  or  sugary  taste. — All  organic  al- 
alkies  are  very  bitter. — Almost  all  acids  have  an  acid  taste. — Almost  all  salts  of  iron 
have  an  inky  taste,  etc. — Substances  with  a  perfumed  smell  are  carburets  of  hy- 
drogen.— Substances  of  fetid  smell  have,  nearly  all  of  them,  arsenic  or  sulphur  in 
their  bases,  etc. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  I2e 

constitutes  a  special  nerve  is  its  capacity  to  arouse  such  ele- 
mentary sensations.  Those  excited  by  the  acoustic  nerve 
correspond  to  undulations  of  the  air  comprised  between  two 
limits.  Those  of  the  optic  nerve  correspond  to  undulations 
of  ether  also  comprised  between  two  limits.  Those  to  which 
the  gustatory  and  olfactory  nerves  give  rise,  correspond  to 
molecular  movements  of  determinate  form. 

Compare,  for  instance,  the  two  sensations  which  the  same 
undulations  of  the  air  excite  through  the  nerves  of  touch,  and 
the  nerves  of  hearing  ;  that  is  to  say,  on  the  one  hand  a  more 
or  less  pronounced  quivering  and  tickling,  and  on  the  other 
hand  a  sound  more  or  less  intense  and  acute.  The  external 
antecedent  is  the  same  in  the  two  cases ;  but  the  elementary 
sensations  excited  through  the  medium  of  the  acoustic  nerve 
correspond  to  the  elements  of  the  undulation  of  the  air,  and 
this  is  not  the  case  with  the  elementary  sensations  excited  by 
the  medium  of  the  nerves  of  touch.  For,  in  fact,  all  details 
and  variations  of  the  undulation  of  the  air  are  represented  in 
the  whole  sensation  of  hearing,  and  are  not  represented  in  the 
whole  sensation  of  touch.  In  the  sensation  of  hearing,  the 
greater  or  less  speed  of  the  waves  is  represented  by  the  great- 
er or  less  acuteness  of  the  sound ;  the  tone,  by  a  supplemen- 
tary group  of  more  feeble  sensations ;  each  wave,  by  an  ele- 
mentary sensation ;  the  depth  of  the  wave,  by  the  intensity 
of  the  sound ;  the  degrees  of  condensation  of  each  wave,  by 
the  degrees  of  intensity  of  the  sound.  With  the  sensation 
of  touch,  on  the  contrary,  the  representation  is  imperfect ;  all 
we  experience  is  that  the  quivering  becomes  stronger,  and  de- 
generates into  a  tickling,  when  the  undulation  becomes  quick- 
er and  the  condensations  of  the  waves  become  stronger. — And 
so  again  another  external  event,  the  undulation  of  an  ether, 
represents  itself  to  us  in  two  ways,  by  the  tactile  sensation 
of  heat  or  cold,  and  the  visual  sensation  of  color  and  light.  In 
the  second  case,  all  the  degrees  of  speed  and  length  which  the 
wave  of  ether  assumes  are  precisely  represented,  but  only 
when  their  speed  and  length  attain  that  of  the  limit  of  red, 
and  do  not  exceed  that  of  the  limit  of  violet.  On  the  contra- 
ry, the  first  translation  represents,  not  only  waves  comprised 
between  the  limits  of  red  and  violet,  but  many  other  waves 


126  OF  SENSATIONS.  [BooK  III. 

situated  outside  those  limits ;  but  none  of  the  waves  are  spe- 
cially represented,  and  the  sensation  of  heat  or  cold  does  but 
roughly  represent  the  difference  of  intensity  separating  two 
systems  of  successive  undulations. 

Thus  the  four  special  senses  are  four  special  languages, 
each  appropriate  to  a  different  subject,  each  admirably  adapt- 
ed to  express  one  order  of  facts,  and  that  order  alone.  Touch, 
on  the  other  hand,  is  a  general  language  applicable  to  all  sub- 
jects, but  not  well  fitted  to  express  the  shades  of  meaning  in 
the  different  subjects.  In  general,  a  sense  is  a  system  of  spon- 
taneous writing  and  of  automatic  notation,  resembling  the  in- 
struments of  measurement  of  which  we  avail  ourselves  in  phys- 
ics and  chemistry.  Sometimes  these  are  delicate  and  special,  as 
the  multiplying  calorimeter,  or  the  instrument  invented  for 
the  self-registration  of  the  movements  of  the  heart ;  sometimes 
they  are  less  delicate  and  of  general  use,  as  the  balance  which 
only  serves  to  denote  the  final  augmentation  or  diminution  of 
weight  in  an  experiment.  Sometimes  the  elementary  sensa- 
tion corresponds,  feature  for  feature,  with  the  element  by 
whose  repetition  the  external  event  is  made  up ;  in  this  case 
the  elementary  sensation  copies,  one  by  one,  the  variations 
of  this  element,  with  their  order  and  magnitude ;  but,  if  we  ap- 
ply it  to  elements  of  another  kind,  it  is  of  no  effect,  or  con- 
fused, or  extreme,  and  unfit  to  represent  them.  Sometimes 
the  elementary  sensation  does  not  thus  correspond,  feature 
for  feature,  to  the  element  whose  repetition  constitutes  the 
external  event,  and  does  not  copy  the  several  variations  of 
this  element ;  but,  in  this  case,  the  external  event,  whatever 
it  be,  excites  a  body  of  elementary  sensations,  the  whole  of 
which  represent  it  as  a  whole,  though  unprecisely  and  in  the 
rough. 

IV.  This  is  the  character  of  touch,  and  we  see  that  it 
differs  from  the  other  senses,  and  that  its  elementary  sensations 
do  not  correspond  to  any  elementary  external  event,  and  so 
cannot  be  referred  to  any  known  type.  Here,  then,  we  are 
confronted  with  a  new  difficulty.  There  is  no  special  event  here, 
as  in  former  instances,  to  serve  as  a  guide  in  discovering  ele- 
mentary sensations.  We  have  to  seek  out  a  new  path  ;  be- 
fore attempting  it,  let  us  see  whether  among  the  sensations  of 


CHAP.  II.]  SENSATIOATS  OF  SIGHT,  ETC. 


127 


touch  we  cannot  find  some  to  which  others  may  be  reduced ; 
we  must  clear  the  ground  before  attempting  to  cultivate  it. 

In  studying  cases  of  partial  paralysis,  physiologists  have 
first  distinguished  two  groups  of  primitive  sensations,  one  com- 
prising sensations  of  the  muscles,  and  the  other  sensations  of 
the  skin,  the  first  having  as  origin  the  excitement  of  the  nerv- 
ous extremities  found  in  the  muscles,  the  second  having  as  or- 
igin the  excitement  of  the  nervous  papillae  found  in  the  derma. 
Each  of  these  two  groups  may  be  missing,  without  the  other 
being  affected. 

When  the  first  is  wanting,  we  see  that  all  the  sensations 
of  muscular  contraction  and  expansion  are  absent,  with  all  their 
several  degrees  of  painful  effort,  fatigue,  and  cramp,  besides 
the  various  sensations  of  cold,  heat,  contact,  pain,  electric  shock, 
produced  by  the  application  of  stimuli  to  the  muscles  in  their 
normal  state.*  "  As  soon  as  the  patients  take  their  eyes  off 
their  limbs,  they  have  no  more  consciousness  of  their  position, 
or  even  of  their  existence.  When  in  bed,  they  lose  them,  as 
it  were,  and  are  obliged  to  look  for  them,  not  knowing  where 
they  are.  Sometimes  they  try  to  stretch  out  or  bend  some 
limb  already  stretched  out  or  bent.  On  moving,  they  are 
ignorant  of  the  extent  of  their  movement,  and  frequently  do 
not  know  whether  they  have  moved  or  not.  If  they  intend 
to  move,  but  are  prevented,  they  are  unaware  of  it,  and  think 
they  have  moved,  from  having  willed  to  do  so.  Passive  move- 
ments may  be  occasioned  in  them  by  means  of  an  electric  ap- 
paratus, without  their  suspecting  it.  Their  limbs  seem  to 
them  deprived  of  weight.  If  their  hands  are  plunged  in  water, 
they  know  by  the  cutaneous  impression  that  it  is  a  liquid,  but 
on  moving  the  hand  about,  they  do  not  experience  that  soft 
resistance  which  gives  the  notion  of  the  fluidity  of  water,  and 
do  not  know  whether  their  hand  is  moving  in  the  air  or  in  the 
water.  If  the  muscles  be  pressed,  pinched,  or  kneaded,  no 
distinct  sensation  takes  place.  They  do  not  perceive  the  pas- 
sage of  an  intense  electric  shock.  A  sharp  instrument  may 
be  stuck  in  their  flesh  without  their  perceiving  it ;  that  is,  un- 
less they  discover  it  through  the  persisting  sensibility  of  the 


*  Axenfeld,  "  Des  Nevroses,"  339. 


128  OF  SENSATIONS.  [BOOK  III. 

skin."  Therefore,  though  they  have  retained  all  their  muscu- 
lar vigor,  and  are  besides  insensible  to  fatigue,  they  walk  with 
great  difficulty  in  the  dark,  or  when  they  cease  to  watch  their 
movements  with  their  eyes  ;  the  sensations  of  sight  must  be 
constantly  present  to  supply  the  place  of  the  absent  muscular 
sensations.  If  both  sensations  fail  them,  "  they  can  hardly 
keep  themselves  upright  without  stumbling  or  running  the 
risk  of  a  fall ;  their  movements  are  either  too  extensive  or 
not  extensive  enough ;  they  readily  let  things  slip  from  be- 
tween their  fingers,  or  sometimes  crush  them  by  too  forcible 
a  contraction."  No  other  sensation  is  missing ;  they  may  still 
feel  all  the  cutaneous  sensations  of  tickling,  contact,  passive 
pressure,  of  superficial  heat  and  pain.  In  other  words,  such 
patients  can  no  longer  estimate  the  state  of  their  muscles,  but 
are  still  perfectly  capable  of  estimating  the  state  of  their  skin. 

There  are  patients,  on  the  other  hand,  unable  to  estimate 
the  state  of  their  skin,  but  who  can  still  estimate  the  state  of 
their  muscles.* — A  workman,  mentioned  by  Landry,  had  his 
fingers  and  hands  insensible  to  all  impressions  of  contact, 
pain,  and  heat ;  but  his  muscular  sensations  were  unaffected. 
If  his  eyes  were  closed,  and  a  somewhat  bulky  object  were 
placed  in  his  hand,  he  was  surprised  at  not  being  able  to  close 
it;  he  had  a  sensation  of  resistance,  but  nothing  more;  he 
could  not  say  what  the  object  was,  what  was  its  form,  size, 
kind,  if  it  was  cold  or  hot,  rough  or  smooth,  or  even  if  there 
was  any  object  there  at  all.  A  weight  of  a  kilogramme  was 
tied  to  his  fist  with  a  string  without  telling  him  what  it  was, 
and  he  thought  some  one  was  pulling  his  arm. 

Here,  then,  we  have  two  groups  of  sensations  and  two 
groups  of  nerves  as  distinct  as  those  of  the  arm  and  leg,f  and, 


*  Landry,  "  Traite  des  Paralysies,"  i.  195,  182,  199. 

f  Brown-Sequard,  "Journal  de  Physiologic,"  vi.  pp.  124-615.  According  to 
Brown-Sequard,  "  sensitive  impressions  of  pain  and  touch  are  transmitted  in  a 
cross  direction  to  the  spinal  marrow,  that  is  to  say,  the  transmission  to  the  brain 
of  impressions  arising  in  one  half  the  body  acts  in  the  lateral  half  of  the  spinal 
marrow  on  the  opposite  side.  On  the  contrary,  impressions  of  muscular  sensation 
pass  without  crossing  to  the  anterior  part  of  the  spinal  marrow."  Consequently 
"  the  conductors  of  muscular  sensation  differ  fundamentally  from  the  conductors  of 
other  sensitive  impressions."  And  the  author  adds,  "  not  only  do  these  conductors 


CHAP.  II.]  SENSATIONS  OF   SIGHT,    ETC. 


129 


we  may. add,  as  similar.  For  the  nerves  of  the  muscles,  like 
those  of  the  skin,  may  give  rise  to  sensations  of  contact,  of 
cold  and  heat,  of  pleasure  and  pain.*  "  Persons  wounded  by 
a  sword-thrust,  or  the  cut  of  a  bistoury,  frequently  feel,  in 
addition  to  the  pain  of  the  wound,  the  chill  of  the  blade  and 
its  presence  in  the  depth  of  the  tissues,  and,  with  many  para- 
lytics, although  the  skin  may  be  quite  insensible  to  all  kinds  of 
stimulation,  a  pressure,  a  shock,  the  pick  of  a  pin-thrust  into 
the  soft  parts,  are  felt  as  deep-seated  impressions  of  contact, 
shock,  and  pain."  Besides,  these  same  nerves  give  us  pain 
when  electricity  is  passed  through  them,  or  when  they  are 
excited  by  a  very  strong  muscular  contraction  ;  and  when  ex- 
cited by  the  expansion  consequent  on  fatigue  and  shampoo- 
ing they  give  pleasure.  In  all  these  respects,  their  action  is 
the  same  as  that  of  the  nerves  of  the  skin,  from  which  they 
only  differ  by  terminating  in  the  muscles,  and  being  excited 
by  the  stretching  out  or  shortening  of  the  muscles.  But  here, 
there  is  no  difference  of  action,  the  difference  is  the  excitant ; 
in  the  strict  muscular  sensation  there  is  nothing  more  than  a 
sort  of  wrenching,  similar  to  the  other  sensations,  and  capable, 
like  them,  of  passing  into  pain  if  pushed  too  far. 

Thus  we  arrive  at  distinguishing  in  the  nerves  of  the 
muscles,  as  in  those  of  the  skin,  three,  and  only  three  kinds  of 
sensations:  those  of  contact,  those  of  heat  and  cold,  those 
of  pleasure  and  pain. — And  further,  we  find  all  three  kinds 
more  or  less  vaguely  present  wherever  there  are  tactile  nerves. 


not  cross  in  their  passage  to  the  spinal  marrow,  but  further,  they  spring  from  this 
organ  principally  if  not  entirely  by  the  anterior  spinal  roots." 

There  are  very  strong  proofs  of  this  theory  in  observations  made  in  cases  of 
wounds  and  lateral  alterations  of  the  spinal  marrow.  We  see  patients  lose  on 
one  side,  the  right  for  instance,  the  power  of  experiencing  sensations  of  touch,  of 
pain,  of  cold,  of  heat,  of  tickling,  and  preserve  on  this  same  side,  not  only  the 
power  of  moving  their  limbs,  but  also  that  of  directing  them  exactly,  and  esti- 
mating all  the  degrees  of  muscular  contraction  ;  the  inverse  is  the  case  on  the  left 
side.  (See  particularly  the  cases  cited,  pp.  238,  582). — In  accordance  with  this 
theory,  the  nerves  and  conductors  of  muscular  sensations  are  not  only  distinct 
from  the  nerves  and  conductors  of  tactile  sensations,  but,  more  than  this,  their 
anatomical  course  is  different,  and  we  can  discover  this  course  in  the  spinal  mar- 
row. 

*  Landry,  "  Traite  des  Paralysies,"  i.  201. 


OF  SENSATIONS.  [BOOK  III 

"  The  internal  surface  of  the  walls  of  the  abdomen  feels 
clearly  the  motion  of  the  intestines After  a  cold  in- 
jection, a  very  plain  sensation  of  cold  is  felt  passing  in  the  direc- 
tion of  the  ascending  and  transverse  colon."*  The  pharynx, 
oesophagus,  and  even  the  stomach,  feel  with  some  degree  of 
exactitude  the  passage,  warmth,  and  presence  of  food.  And, 
in  general,  let  us  review  successively  the  innumerable  internal 
sensations,  agreeable,  painful,  or  indifferent,  of  organic  life, 
those  constituting  hunger,  thirst,  and  repletion,  those  accom- 
panying digestion,  respiration,  circulation,  copulation,  or 
speech,  those  produced  by  wine,  medicines,  and  various  sub- 
stances introduced  into  the  circulation,  besides  all  the  spon- 
taneous sensations,  tinglings,  itchings,  shiverings,  all  the  vari- 
ous hardly  definable  pains  which  serve  as  symptoms  of  differ- 
ent illnesses,  all  the  special  and  very  delicate  sensations  of 
touch  we  meet  with  in  the  conjunctiva,  the  tongue,  and  the 
interior  of  the  nostrils,  all  the  general  and  blunted  sensations 
of  touch  such  as  we  find  on  the  surface  of  the  wound  after  a 
recent  amputation  :  we  shall  see  that  they  are  sensations  of 
contact,  of  cold  or  heat,  of  pleasure  or  pain,  more  or  less  ob- 
scure, more  or  less  ill-defined,  more  or  less  spread  about,  the 
same  in  substance,  but  diversified  by  their  situation,  the  order 
of  their  phases,  and  the  degree  of  their  intensity.f  We  shall 

*  Landry,  "  Traite  des  Paralysies,  "  i.  201.  Longet,  "  Traite  de  Physiologic," 
ii.  179- 

f  Numbers  of  sensations  which  seem  to  have  a  special  type  and  to  be  sui gene- 
ris, are  composed  of  elementary  sensations  of  contact.  "  If,"  says  M.  Landry, 
"  we  cover  a  polished  surface  with  a  thin  layer  of  talc  and  get  a  person  who  is  not 
aware  of  this  to  pass  the  tip  of  his  finger  over  it,  he  will  imagine  he  is  touching  a 
greasy  or  oily  body.  .  .  ." — Again,  if  we  sprinkle  some  drops  of  water  on  a  marble 
table,  and  then,  with  our  eyes  shut,  place  the  tip  of  a  finger  alternately  on  the  dry 
and  the  wet  spots,  we  shall  not  be  able  to  distinguish  one  from  the  other.  There 
is  no  special  sensation,  then,  of  damp  or  stickiness,  but  a  compound  sensation  of 
touch.  "  This  sensation,"  says  M.  Gratiolet,  "  is  developed  when  the  skin  detaches 
itself  from  something  sticking  to  it,  as,  for  example,  a  surface  covered  with  diachy- 
lon. It  is  most  clear  and  distinct  at  the  moment  the  adhesion  comes  to  an  end, 
and  the  skin  which  had  been  drawn  by  the  surface  suddenly  returns  to  its  proper 
state.  From  this  sensation,  when  it  is  strong,  comes  the  idea  of  viscidity  ;  when 
slight,  that  of  humidity.  The  contrary  notion  of  dryness  is  derived  from  an  abso- 
lute want  of  adherence.  This  is  so  far  the  case  that  when  the  hand  is  plunged  in 
water  we  do  not  feel  this  humidity,  nor  when  it  is  plunged  in  oil  do  we  feel  its  oili- 
ness.  In  fact,  bodies  which  an  intermediate  layer  of  water  cause  to  adhere  to  vis, 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  J^l 

find  no  other  element  in  them,  and,  by  this  first  reduction, 
we  bring  tactile  sensations  under  three  types,  and  three  only. 
These  types  are  not  only  distinct,  but  separable ;  each  of 
them,  as  far  at  least  as  sensations  of  the  skin  are  concerned, 
may  severally  be  lost,  while  the  other  two  are  retained.* — 
In  some  cases  the  sensation  of  pain  only  is  lost.  Patients  still 
perceive  the  other  cutaneous  sensations,  such  as  heat,  contact, 
tickling,  and  can  recognize  the  touch  of  a  finger,  the  brushing 
of  a  quill,  the  contact  of  a  pin ;  but  if,  in  the  same  spot,  we  prick 
them  with  the  pin,  it  occasions  no  pain.  "I  can  feel,"  said 
one  of  them, "  that  you  prick  and  pinch  me,  but  you  do  not 
hurt  me."  This  is  carried  so  far  that  sometimes  the  applica- 
tion of  a  white-hot  cauterizing  iron  gives  no  pain.  A  girl, 
suffering  from  hysteria,  at  the  Hopital  Saint-Antoine,  upset 
boiling  water  over  her  hands,  and  did  not  find  it  out  till  she 
saw  large  blisters  rising. — In  other  cases,  sensations  of  heat 
and  cold  are  alone  wanting.  The  patient  then  says  : — "  I  feel 
the  form  and  consistency  of  the  body  touching  me,  but  cannot 
tell  whether  it  is  hot  or  cold." — Finally,  in  other  cases,  the 
sensation  of  touch  only  is  wanting.  Here,  for  instance,  the 
patient  does  not  feel  small  objects  placed  between  the  tips  of 
his  fingers  ;  but"  if  pricked  there,  even  superficially,  it  is  plain- 
ly felt." — On  the  other  hand,  each  type  of  sensation  may  sub- 
sist alone,  the  other  two  being  lost.  Some  patients  who  no 
longer  feel  sensations  of  pain  or  heat,  still  feel  contact  at  the 
same  point.  Others  more  numerous,  no  longer  feel  sensations 
of  pain  and  contact,  but  those  of  temperature  only.  Others 
finally,  who  can  still  feel  pain,  cannot  feel  heat  or  contact. 
It  is  plain  that  each  of  these  three  types  of  sensation  has  its 


no  longer  adhere  when  plunged  in  water,  and  so  with  bodies  plunged  in  oil.  .  .  . 
The  skin  i  >  i  apable  of  receiving  impressions  on  two  layers — the  one  superficial, 
the  other  deep-seated.  When  the  sensibility  of  the  deep-seated  layer  is  brought 
into  play,  the  sensation  of  pressure  arises." — Gratiolet,  "  Anatomic  Comparee  du 
Systeme  Nerveux,"  ii.  409.  Landry,  "  Paralysies,"  159,  179. 

*  Beau,  "Archives  Generates  de  Medecine,"  Janvier,  1848. — Delacour,  these, 
Janvier,  1850. — Landry,  "  Recherches  sur  les  Sensations  Tactiles." — "  Traite  des 
Paralysies." — Axenfeld,  "  Des  Nevroses,"  332. 

This  separation  has  not  been  observed  in  the  muscular  sensations  ;  when  any 
of  them  disappear,  the  others  disappear  as  well. 


!32  OF  SENSATIONS.  [BOOK  III. 

special  conditions,  and  when  these  conditions  alone  are  abol- 
ished, or  alone  preserved,  the  isolated  abolition  or  preservation 
of  the  type  ensues.  Experience  has  discovered  some  among 
these  conditions.  If  a  limb  is  chilled  up  to  a  certain  fixed 
point,  it  retains  the  sensation  of  contact,  but  ceases  to  expe- 
rience that  of  pain ;  for  instance,  "  if  we  apply  to  the  knee 
a  mixture  of  pounded  ice  and  sea-salt  in  the  proportion  of 
two  parts  of  ice  to  one  of  salt,  the  skin  becomes  bloodless,  and 
we  may  cauterize  the  limb  without  the  patient  feeling  any 
other  sensation  than  that  of  the  pressure  of  the  iron."  Thus, 
the  sensation  of  pain  is  subject  to  a  special  condition ;  to 
produce  it,  the  circulation  of  the  blood,  and  therefore  the  mo- 
lecular wastings  and  repairs  of  the  nerve,  must  go  on  with  a 
certain  degree  of  speed.  With  a  less  degree  the  nerve  is  no 
longer  capable  of  the  special  type  of  action  which  arouses  the 
sensation  of  pain,  though  it  may  still  be  capable  of  the  special 
type  of  action  which  arouses  the  sensation  of  pressure  and  of 
contact. — We  see  that  the  sensation  of  pain  requires  for  its 
production  a  condition,  additional  to  those  required  by  the 
sensation  of  contact ;  hence  it  follows  that  it  may  readily  be 
abolished  without  inducing  the  abolition  of  the  sensation  of 
contact,  and  that  the  reverse  is  not  the  case ;  this  is  in  con- 
formity with  experience.  Persons  who  have  lost  all  sensations 
of  pain  frequently  retain  sensations  of  contact ;  but  very  sel- 
dom do  persons  who  have  lost  sensations  of  contact  retain 
those  of  pain.* 

This  instance  puts  us  in  the  track  of  the  needed  expla- 
nation. In  fact,  we  have  no  need  to  suppose,  with  many 
physiologists,  that  there  are  three  kinds  of  nerves  intended 
to  transmit  impressions  of  contact,  of  heat  and  cold,  and  of 
pain  respectively ;  each  of  the  three  classes  being  capable  of 
being  paralyzed  singly,  and  of  thus  cutting  away  from  us  one 
kind  of  sensation  without  the  other  kinds  being  thereby  abol- 
ished. The  only  thing  which  the  facts  attest  is,  that  the  three 
kinds  of  sensations  have  special  conditions,  and  that  these  con- 


*  Axenfeld,  ibid.,  332.  "  The  inverse  case  is  rarely  seen  ;  when  the  sense  of 
touch  is  lost,  that  of  pain  is  lost  at  the  same  time,  or,  in  other  words,  the  existence 
of  anaesthesia,  strictly  so  called,  almost  invariably  implies  that  of  analgesia." 


CHAP.  II.]  SENSATIONS  OF  SIGHT,   ETC. 


133 


ditions  may  be  singly  destroyed. — What  are  these  conditions  ? 
We  may  conceive  many  kinds. — They  may  be  anatomical ;  this 
is  the  answer  of  the  physiologists,  of  Landry,  Brown-Sequard, 
and  Lhuys.  In  fact,  it  is  sufficient  for  the  explanation  of 
these  isolated  abolitions  that  there  be  three  kinds  of  nerves  ;  this 
solution  is  a  manifest  one,  we  are  tempted  to  adopt  it.  But 
there  are  others,  for  the  presence  of  a  special  nerve  does  not 
necessarily  follow  from  the  fact  of  a  special  condition. — There 
are  two  other  possible  explanations.  First,  the  condition  may 
be  a  special  state  of  the  same  nerve,  which  would  appear  to  be 
the  case  from  the  experiment  in  which  the  frozen  knee  becomes 
bloodless.  Secondly,  the  condition  may  be  a  special  state  of 
the  parts  surrounding  the  nerve,  and  through  which  the  ex- 
ternal stimulus  acts  on  the  nerve  ;  in  this  case,  the  same  nerve, 
under  the  influence  of  the  same  external  stimulus,  would  trans- 
mit different  sensations,  according  as  the  parts  between  it  and 
the  stimulus  were  in  different  states.  These  last  solutions  are 
more  abstract,  but  they  agree  better  with  the  facts. 

Weber's  experiments  appear  to  me  conclusive  as  to  this.* 
— If  we  dip  into  cold  water  a  large  nervous  trunk,  for  instance, 
the  cubital  nerve,  where  it  springs  from  between  the  two  bones 
at  the  elbow,  we  find,  in  accordance  with  a  well-known  law,  a 
sensation  in  the  arm  and  two  last  fingers  of  the  hand,  occa- 
sioned by  the  nervous  action  going  on  at  the  elbow ;  now  this 
sensation  is  not  of  cold,  but  simply  of  pain.  Consequently, 
when  we  have  a  sensation  of  cold,  it  is  not  owing  to  the  im- 
mediate action  of  cold  on  the  nerve ;  for  it  was  not  felt  just 
now,  when  the  cold  was  acting  immediately  on  the  cubital 
nerve.  In  order  to  feel  it,  the  cold  must  act  indirectly;  that 
is  to  say,  through  certain  parts  adjacent  to  the  nerve,  certain 


*  Article  Tastsinn,  498,  in  "  Handbuch  der  Physiologic,"  by  Rudolf  Wagner. 

Cf.  Fick,  "  Anatomie  und  Physiologic  der  Sinnes  Organe,"  28,  30,  42,  43. 
From  the  anatomical  structure  of  the  organs  of  touch,  he  shows,  by  approximation 
and  hypothesis,  the  different  types  of  action  which  excite  in  the  same  nerve  dif- 
ferent sensations,  that  of  heat  or  cold,  that  of  pressure  or  contact.  "  It  is  probable 
that  the  stimulation  of  the  nerves,  in  the  sensation  of  heat  or  cold  at  the  sensible 
periphery  of  the  skin,  is  not  immediately  developed  by  a  change  of  temperature 
of  the  nervous  substance  itself,  but  by  the  simultaneous  changes  supervening  in  the 
mechanical  relations  of  the  terminal  corpuscles." 


1 34  OF  SENSA  TIONS.  [BooK  III. 

organs  disposed  for  this  purpose  ;  these  act  directly  on  the 
nerve  ;  the  cold  modifies  them,  and  their  modification  impress- 
es on  the  nerve  a  special  type  of  action,  which  excites  in  us 
the  special  sensation  of  cold. — If,  on  the  contrary,  without 
paralyzing  the  nerve,  we  simply  destroy  in  these  adjacent 
parts  the  property  they  have  of  impressing  this  rhythm  of  ac- 
tion on  the  nerve,  we  shall  cease  to  have  the  special  sensation 
of  cold ;  when  the  cold  begins  to  act  on  the  nerve,  it  will  no 
longer  excite  the  special  sensation  of  cold,  and  will  only  ex- 
cite, as  we  found  just  now  in  the  case  of  the  cubital  nerve, 
the  sensation  of  pain.  This  is  what  happens  in  certain  illness- 
es. M.  Axenfeld  writes  as  to  this — "  With  ataxic  persons, 
whose  cases  are  among  those  in  which  want  of  sensibility  is 
most  complete,  I  have  often  observed  that  cold  was  disagree- 
able without  its  being  recognized  as  cold.  When  we  ques- 
tion them  as  to  the  nature  of  their  perception,  all  we  can  get 
from  them  is,  '  It  hurts  me.'  " — We  are  led  to  the  same  con- 
clusion by  studying  the  sensations  of  persons  whose  bodies 
present  large  cicatrices,  consequent  on  amputations  or  other 
wounds.  "  The  parts  of  the  skin,"  says  Weber,  "  in  which 
the  tactile  organs  have  been  destroyed,  and  are  not  complete- 
ly reproduced,  cannot  distinguish  heat  and  cold." — Similar 
experiments  point  out  the  presence  of  similar  media  in  the 
case  of  the  sensation  of.  pressure.  If  the  cubital  nerve  be- 
tween the  two  bones  of  the  elbow  be  pressed  with  the  finger, 
the  sensation  in  the  fingers  and  forearm  is  not  of  pressure, 
but  solely  of  dull  pain.  "  Therefore,"  says  Weber,  "  the  sen- 
sation of  pressure,  and  the  power  of  distinguishing  its  numer- 
ous and  different  degrees,  are  only  possible  when  the  pressure 
acts  on  the  organs  of  touch,  and,  through  them,  on  the  extrem- 
ities of  the  tactile  nerves ;  this  sensation  does  not  arise  when 
the  tactile  nerves  are  directly  compressed." — Consequently, 
the  sensation  of  pressure  has  for  its  special  condition,  not  the 
pressure  of  the  nerve,  but  a  certain  modification  of  certain 
organs  or  parts  surrounding  the  nerve.  If  these  organs  be 
alone  destroyed,  or  their  capacity  for  undergoing  this  modifi- 
cation he  alone  suppressed,  the  sensation  of  pressure  will  alone 
be  abolished. 

Thus,  in  all  cases,  what  is  excited  in  us  is  a  special  type 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  iy 

of  action  in  the  nerve,  and  what  excites  this  special  type  of 
action  in  the  nerve  is  a  special  modification  of  its  appendages 
and  dependent  parts. — Consequently,  to  explain  the  three 
kinds  of  tactile  sensations,  and  to  comprehend  how  they  may 
be  singly  abolished,  there  is  no  necessity  of  supposing  themf 
excited  in  us  by  distinct  nerves  of  three  different  kinds :  this 
is  a  gratuitous  hypothesis  which  no  vivisection  or  microscopic 
observation  comes  in  to  confirm.  It  is  enough  to  admit  that 
the  same  nerve  or  group  of  nerves  is  capable  of  many  differ- 
ent types  or  rhythms  of  action,  and  that  each  of  these  rhythms 
is  directly  excited  by  the  special  modification  which  the  ex- 
ternal agents  impress  on  the  parts  surrounding  the  nerve, 
whether  on  the  tubes  containing  it,  or  on  the  blood  washing 
it,  or  on  some  other  of  its  internal  accompaniments. 

It  is  not  impossible  to  form  a  notion  of  the  differences  of 
these  rhythms.  "  Each  tactile  nervous  fibre,"  says  Fick,  "  can 
only  transmit  one  and  the  same  sensation  which  is  capable 

only  of  degrees But  ordinary  external  stimuli  do  not 

arrive  at  these  isolated  elementary  fibres  ;  they  come  in  con- 
tact with  a  group  of  fibres  taken  together.  We  may  suppose 
that  heat  reaches  these  fibres  in  a  different  order  from  pres- 
sure."— "  In  fact,  the  nearer  we  draw  to  the  true  elementary 
sensation,  the  more  does  the  difference  between  the  sensation 
of  heat  and  that  of  a  mechanical  stimulus  seem  to  vanish. 
For  instance,  we  can  hardly  distinguish  a  prick  with  a  very 
fine  needle  from  the  touch  of  a  spark  of  fire." — There  is  a 
further  analogy ;  we  know  that  the  sensations  of  heat  and 
cold,  like  those  of  pressure,  become,  when  carried  beyond  a 
certain  point,  pure  pain. — "  Lastly,  place  on  the  skin  some 
imperfectly  conducting  body ;  for  instance,  a  piece  of  paper, 
pierced  with  a  hole  of  from  2  to  5  millimetres  in  diameter ; 
through  this  hole  apply  to  the  skin,  first,  a  mechanical  stimu- 
lus, a  pointed  piece  of  wood,  a  pencil  or  a  flock  of  wool ;  then, 
a  heated  stimulus,  such  as  the  radiation  from  a  piece  of  hot 
metal."  The  two  sensations,  when  thus  limited  to  a  minimum 
of  nervous  elements,  are  so  similar  that  the  subject  of  the  ex- 
periment frequently  mistakes  the  sensation  of  heat  for  one  of 
contact,  and  that  of  contact  for  one  of  heat, — On  the  contrary, 
when  the  nervous  elements  are  numerous,  as  when  a  large 


OF  SENSATIONS.  [BOOK  III. 

surface  of  the  skin  is  subjected  to  the  same  experiments,  there 
is  not  this  confusion. — Plainly,  then,  here  as  before,  the  ordi- 
nary sensation  is  a  whole  ;  and,  here  as  before,  two  whole  sen- 
sations may  be  apparently  irreducible  to  one  another,  though 
their  elements  may  be  the  same  ;  for  this  it  is  enough  if  the 
little  composing  sensations  differ  in  number,  magnitude,  order 
and  duration ;  their  wholes  form  masses  indivisible  by  con- 
sciousness, and  seem  simple  facts,  differing  in  essence  and  op- 
posed in  quality. 

It  is  very  probable  that  the  sensation  of  pain  is  no  more 
than  a  maximum  ;  for  all  the  others,  pressure,  tickling,  cold, 
heat,  change  into  pain  when  carried  beyond  a  certain  limit. 
— It  is  very  probable  that  the  sensation  of  pressure  only  differs 
from  contact  because  in  pressure  "  the  terminal  corpuscles  of 
the  deep-seated  system  are  also  engaged,  while  in  contact  they 
are  not  so."41  —The  sensation  of  tickling  is  most  probably 
nothing  more  than  a  high  degree  of  the  sensation  of  touch ; 
for,  writes  M.  Axenfeld,  "  I  have  always  found  it  disappear 
with  the  sensation  of  touch."  And,  in  fact,  the  contact  pro- 
ducing it,  though  apparently  feeble,  is  actually  excessive  ;  the 
feather  of  the  quill,  or  the  piece  of  string  which,  when  drawn 
slowly  along  the  cheek  or  across  the  nose,  grazes  imperceptibly 
the  extremity  of  a  nervous  papilla,  evidently  excites  consid- 
erable activity  in  the  terminal  molecule  of  the  papilla,  for  the 
sensation  is  a  most  vivid  one  and  lasts  for  some  seconds  after 
the  touch.  The  alteration  of  equilibrium  in  the  nerve  indica- 
ted by  it  is  greater  and  slower  in  disappearing  than  when  a 
pressure  drives  back  uniformly  a  whole  group  of  papillae;  if 
the  whole  displacement  of  flesh  is  then  much  greater,  the 
relative  displacement  of  the  nervous  molecules  is  much  less. 
This  is  why  the  final  sensation,  if  of  less  extent,  is  far  more 
vivid. 

To  sum  up ;  all  that  observation  shows  us  in  the  nerves 
of  touch,  are  different  systems  of  transmissible  molecular  dis- 


*  See  Fick  and  Gratiolet  at  the  places  mentioned.  Cicatrices  have  no  sensa- 
tion of  heat,  and  only  a  dull  sensation  of  pain,  but  they  retain  the  sensation  of 
pressure.  This  arises  from  the  terminal  epithelial  corpuscles  being  lost,  while  the 
deep-seated  corpuscles  of  Pacini  are  still  there. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,   ETC.  i^j 

placements.  Composed  of  similar  elements,  they  constitute 
dissimilar  types  or  rhythms  ;  undefinable  by  us  in  the  present 
state  of  science,  they  are,  like  all  displacements,  definable  in 
themselves,  by  the  speed,  magnitude,  and  order  of  their  ele- 
ments; and  we  may  admit  that,  according  to  the  order  of 
their  elements,  they  arouse  in  us  sensations,  sometimes  of 
temperature,  sometimes  of  contact  or  pressure  ;  that  at  their 
minimum  of  speed  and  magnitude,  they  arouse  feeble  sensa- 
tions of  pressure,  contact,  and  temperature ;  at  their  maxi- 
mum of  speed  and  magnitude,  they  excite  in  us  the  sensation 
of  pain. 

V.  Let  us  attempt  to  cast  a  general  glance  over  all  these 
facts.  A  sensation  of  which  we  are  conscious  is  a  compound 
of  more  simple  sensations,  which  are  themselves  composed  of 
others  still  simpler,  and  so  on.  Thus  the  sensation  produced 
by  a  harmony  of  thirds,  ut  mi,  is  made  up  of  two  simultaneous 
sensations  of  sound,  ut  and  mi.  Again,  the  sensation  of  ut, 
like  that  of  mi,  is  made  up  of  a  comparatively  strong  sensation, 
that  of  ut,  with  the  addition  of  other  comparatively  feeble 
simultaneous  sensations,  those  of  the  superior  harmonics.  As 
to  this  comparatively  strong  sensation  and  these  compara- 
tively weak  ones,  each  is  made  up  of  shorter  successive  sensa- 
tions, which,  when  isolated,  are  still  perceptible  by  conscious- 
ness, and  whose  number  is  equal  to  that  of  the  vibrations  of 
the  air  divided  by  two.  Each  of  these  little  sensations  is,  in 
its  turn,  composed  of  two  successive  elementary  sensations, 
which,  taken  si  igly,  are  not  perceptible  to  consciousness.  Fi- 
nally, each  of  these  elementary  sensations  is  itself  an  infinite 
series  of  successive  sensations,  equally  imperceptible  to  con- 
sciousness, infinitely  short,  and  increasing  from  a  minimum  to 
a  maximum  through  an  infinite  number  of  intermediate  stages. 
The  whole  results  in  the  sensation  of  the  chord  ut  mi,  a  com- 
pound of  the  fifth  degree,  just  as  a  nroduct  in  organic  chem- 
istry.— So,  again,  the  sensation  of  white  is  composed  in  the 
first  place  of  as  many  partial  and  simultaneous  sensations  of 
white  as  there  are  nervous  fibres  excited  in  the  retina.  Sec- 
ondly, every  partial  sensation  of  white  is  constituted  by  simul- 
taneous sensations  of  two,  or  more  than  two,  complementary 
colors,  for  instance,  yellow  and  indigo.  Thirdly,  the  sensation 


I38  OF  SENSATIONS.  [BOOK  III. 

of  yellow,  like  that  of  indigo,  is  made  up  of  three  element- 
ary and  simultaneous  sensations  of  color,  red,  violet,  and  green, 
each  having  a  particular  degree  of  intensity.  Fourthly,  each 
of  these  three  elementary  sensations  is  composed  of  successive 
and  continuous  sensations  of  the  same  color,  sensations  still 
perceptible  to  consciousness,  and  so  numerous  that  there  are 
at  least  a  million  of  them  in  a  second.  Fifthly,  each  of  these 
successive  sensations,  so  prodigiously  short,  is,  according  to 
all  analogies,  composed  like  those  of  sound,  of  still  shorter 
successive  sensations,  imperceptible  to  consciousness,  like  the 
primitive  sensations  of  sound.  Finally,  if  we  follow  out  our 
analogies  to  the  end,  we  are  led  to  conceive  the  sensation  ex- 
cited by  each  elementary  wave  of  ether  on  the  model  of  the 
sensation  excited  by  each  elementary  wave  of  air,  that  is  to 
say,  as  an  infinite  series  of  successive  sensations  infinitely  short 
and  increasing  from  a  minimum  to  a  maximum  through  an 
infinite  number  of  degrees.  Such  is  the  sensation  of  white, 
a  compound  of  the  fifth  or  sixth  degree. 

This  analysis  brings  three  important  principles  to  light. 
— The  first  is  that  two  successive  sensations  which,  singly, 
are  insensible  to  consciouness,  may,  when  combined,  form 
a  total  sensation  which  consciousness  perceives. — The  second  is 
that  a  sensation  indecomposable  by  consciousness,  and  appar- 
ently simple,  is  a  compound  of  successive  simultaneous  sen- 
sations which  are  themselves  highly  complex. — The  third  is 
that  two  sensations  of  the  same  kind  and  differing  only  in  the 
magnitude,  order,  and  number  of  their  elements,  appear  to 
consciousness  as  irreducible  to  one  another,  and  as  possessed 
of  special  qualities  absolutely  different. — Armed  with  these 
three  principles,  we  can  conceive  the  nature  and  diversity  of 
the  sensations  of  the  other  senses.  In  accordance  with  the 
second  and  third,  smells,  which  like  the  color  white,  appear 
simple  sensations,  are,  like  white,  compound  sensations,  and 
the  different  smells,  which  like  different  tones,  seem  irreducible 
to  one  another,  are,  like  these  different  tones,  wholes,  which, 
composed  of  the  same  elements,  differ  only  in  the  magnitude, 
order,  and  number  of  these  elements.  We  may  form  the 
same  conclusion  with  respect  to  tastes,  and  the  sensations  of 
touch. — But  here  a  difference  appears. — With  smells  and 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC. 

tastes  an  advance  may  be  made  which  cannot  be  made  with 
sensations  of  touch.  An  idea  may  be  formed  of  the  elemen- 
tary sensations  of  which  sensations  of  smell  and  taste  are  con- 
stituted, but  not  of  those  of  which  tactile  sensations  are  con- 
stituted. We  prove  that  the  special  and  immediate  antece- 
dent which  sets  the  olfactory  nerves  and  gustatory  nerves  in 
action  is  a  system  of  molecular  displacements ;  we  conceive 
his  system  of  displacements  to  be  represented  in  the  nerves 
by  a  corresponding  system  of  nervous  actions,  and  to  repre- 
sent itself  to  us  by  a  corresponding  system  of  elementary  sen- 
sations of  taste  and  smell;  we  define,  to  a  certain  exteat, 
these  unknown  elementary  sensations  by  saying  that  they 
correspond  to  molecular  movements  of  chemical  action,  as  the 
known  elementary  sensations  of  hearing  or  sight  correspond 
to  waves  of  the  undulations  of  air  or  ether. — There  is  nothing 
similar  in  the  case  of  touch ;  we  have  no  means  of  determining 
or  conjecturing  the  rhythm  of  action  impressed  on  the  tactile 
nerves  and  transmitted  by  them  to  the  nervous  centres.  The 
elementary  nervous  action,  and  consequently  the  elementary 
tactile  sensation,  remain  beyond  our  grasp.  All  we  know  is 
that  there  is  such  an  action,  and  therefore  such  a  sensation  ; 
for  whatever  be  the  stimulus,  the  tactile  nerve  and  the  cen- 
tres it  is  connected  with  always  act  alike  and  in  a  way  peculiar 
to  them :  their  rhythm  of  action  is  special  and  unalterable ; 
this  is  proved  by  the  rhythm  invariably  exciting  in  us  the 
same  kind  of  sensation,  and  from  this  kind  of  sensation  being 
excited  by  it  alone. 

Here  are  great  gaps  ;  they  will  only  be  filled  when  phys- 
iology is  sufficiently  advanced  to  determine  the  form  and  speed 
of  the  molecular  movement,  whose  repetition  constitutes  ner- 
vous acting.  Meanwhile  the  theory  of  sensation  is  like  a  build- 
ing in  part  completed,  and  in  part  planned  out. — Still  this 
incomplete  construction  is  sufficient  to  give  us  an  idea  of  the 
whole.  We  see  that  the  innumerable  sensations  which  we 
refer  to  one  sense  may  be  reduced  in  each  case  to  an  elemen- 
tary sensation  whose  different  groupings  make  up  the  different 
sensations  of  that  sense.  We  conceive,  in  accordance  with 
the  three  principles  laid  down,  that  the  elementary  sensations 
of  the  five  senses  may  themselves  be  wholes,  composed  of  the 


140  OF  SENSATIONS.  [BOOK  III. 

same  elements,  without  other  difference  than  that  of  the  num- 
ber, order,  and  magnitude  of  these  elements,  and  therefore,  like 
the  distinct  sensations  of  hearing  or  sight,  they  may  be  reduced 
to  a  single  type.  If  so,  there  would  be  but  one  elementary 
sensation  capable  of  various  rhythms,  as  there  is  but  one  ner- 
vous texture  capable  of  various  types.* — And  in  fact,  what- 
ever may  be  the  structure  of  the  nerves  and  nervous  centres 
whose  action  excites  a  sensation,  however  various  this  struc- 
ture may  be  supposed,  that  which  is  transmitted  from  one  end  of 
the  nerve  to  the  other  up  to  the  ultimate  nervous  centre,  is 
n,ever  more  than  a  molecular  displacement,  more  or  less  rapid, 
extensive,  and  complex.  A  particle  had  a  certain  situation 
with  respect  to  others ;  this  situation  changes,  that  is  all ;  at 
the  limit  of  all  the  sciences  relating  to  bodies  we  invariably 
find  mechanics.  So  that  the  different  nervous  actions  which 
excite  different  sensations,  can  only  be  conceived  as  sys- 
tems of  movements.  Thus  all  these  actions,  though  dif- 
fering in  quantity,  are  the  same  in  quality. — Now  since,  by 
the  known  correspondence  between  the  sensation  and  the 
nervous  action,  sensations  different  in  quantity  are  the  same 
in  quality,  we  arrive,  by  deduction,  at  the  result  foreshad- 
owed by  analogy. — At  the  foundation  of  all  bodily  events 
we  find  an  infinitesimal  event,  imperceptible  to  the  senses, 
movement,  whose  degrees  and  complications  constitute  the 
rest,  whether  the  phenomena  be  physical,  chemical,  or  phys- 
iological. At  the  foundation  of  all  moral  events,  we  guess 
the  presence  of  on  infinitesimal  event,  imperceptible  to  con- 
ciousness,  whose  degrees  and  complications  make  up  all 


*  Fick,  "  Lehrbuch  der  Anatomic  und  Physiologic  der  Sinnesorgane,"  5.  Der 
Erregungsvorgang,  welche  Form  er  auch  immer  haben  mag,  ist  in  alien  nervo'sen 
Elementen  gleicher  Art,  also  ins  besondere,  in  alien  Nervenfasern,  derselbe,  sei 
dieser  Faser  im  Hirn,  im  Ruckenmark,  oder  in  einem  peripherischen  Nervenstamm. 
.  .  .  Indessen  ist  doch  sehr  \varhscheinlich,  dass  der  Erregungsvorgang  in  den 
nervo'sen  Elementen  in  gewissen  Drehungen  oder  Umgruppirungen  electromoto- 
rischen  molecule  besteht. 

See  also  Dr.  Onimus,  "  De  la  Vibration  Nerveuse  et  de  1'action  reflexe  dans 
les  Phfinomenes  Intellectuels." 

Many  physiologists  admit  that  this  displacement  of  the  nervous  molecules  may 
be  compared  to  a  vibration  or  to  the  swing  of  a  pendulum.  At  all  events,  there 
is  an  order  of  positions,  which  is  altered,  and  then  re-established. 


CHAP.  II.]  SENSATIONS  OF  SIGHT,  ETC.  I4! 

the  rest,  sensations,  images,  and  ideas.  What  is  this  sec- 
ond event,  and  can  we  reduce  one  of  these  events  to  the 
other? 

Meanwhile  we  have  reached  the  foundations  of  human 
knowledge,  and  are  capable  of  estimating  their  solidity. — We 
have  seen  that  our  senses  are  idioms,  of  which  four  are  special 
and  the  last  general.  A  sensation  is  a  mental  representative, 
the  internal  sign  of  the  external  fact  exciting  it.  The 
special  sensations  of  sight,  hearing,  smell,  and  taste  are  deli- 
cate and  limited  representatives,  each  of  which  severally  trans- 
lates accurately,  by  its  characteristics,  a  special  order  of  ex- 
ternal facts.  The  general  sensations  of  touch  are  coarse  uni- 
versal representatives  translating,  by  their  characteristics, 
nearly  all  the  orders  of  external  facts.  Thus,  every  normal 
sensation  corresponds  to  some  external  fact  which  it  trans- 
cribes with  greater  or  less  approximation,  and  whose  internal 
substitute  it  is.  By  this  correspondence,  internal  events  agree 
with  external,  and  sensations,  which  are  the  elements  of  our 
ideas,  find  themselves  naturally  and  beforehand  adjusted  to 
things,  which  adjustment  will,  further  on,  enable  our  ideas  to 
be  in  conformity  with  things,  and  consequently  true. — On  the 
other  hand,  we  have  seen  that  images  are  substitutes  for  sen- 
sations, past,  future,  or  possible,  that  individual  names  are 
substitutes  for  images  and  sensations  momentarily  absent,  that 
the  more  simple  general  names  are  substitutes  for  images  and 
impossible  sensations,  that  the  more  complex  general  names 
are  substitutes  for  other  names,  and  so  on. — It  seems  then 
that  nature  has  undertaken  to  provide  in  us  representatives 
of  her  events,  and  has  effected  her  purpose  in  the  most  econom- 
ical way.  She  has  provided,  first,  the  sensation  which  trans- 
lates the  fact  with  more  or  less  precision  and  delicacy ;  then, 
the  surviving  sensation  capable  of  indefinite  revival,  that  is  to 
say,  the  image,  which  repeats  the  sensation,  and  consequently 
translates  the  fact  itself;  then,  the  name,  a  sensation  or  image 
of  a  particular  kind,  which,  by  virtue  of  its  acquired  properties, 
represents  the  general  character  of  many  similar  facts,  and  re- 
places the  impossible  images  and  sensations  which  would  be 
necessary  to  translate  this  isolated  character.  By  means  of 
this  correspondence,  of  this  repetition,  and  this  replacement, 


I42  OF  SENSATIONS.  [BOOK  III. 

external  facts,  present,  past,  future,  special,  general,  simple, 
or  complex,  have  their  internal  representatives,  and  this  men- 
tal representative  is  always  the  same  internal  event,  more  or 
less  compounded,  repeated,  and  disguised. 


CHAP.  I.]    FUNCTIONS  OF  THE  NERVOUS  CENTRES. 


BOOK  IV. 

OF  THE  PHYSICAL  CONDITIONS  OF  MENTAL  EVENTS. 


CHAPTER  I. 

OF  THE  FUNCTIONS  OF  THE  NERVOUS  CENTRES. 

I.  WE  must  stop  here  and  change  our  route ;  we  have 
come  to  the  end  of  psychological  analysis ;  let  us  see  how  far 
physiological  analysis  will  carry  us. 

We  have  explored,  as  geologists,  a  great  country,  from  its 
highest  peaks  to  its  seaboard,  and,  through  all  the  accidents 
of  surface,  have  recognized  one  and  the  same  stratum  sup- 
porting all  the  different  varieties  of  soil.  From  our  most  ab- 
stract ideas  to  our  crudest  sensations,  we  have  constantly 
found  the  same  fundamental  layer ;  ideas  are  sensations  or 
images  of  a  certain  kind ;  images  themselves  are  sensations 
capable  of  spontaneous  revival.  At  the  foundation  of  all  these, 
we  invariably  find  the  sensation.  But,  when  we  come  to  the 
sensation,  we  are  at  the  limits  of  the  mental  world  ;  between 
it  and  the  physical  world  there  is  a  gulf,  and,  as  it  were,  a 
deep  sea ;  we  can  no  longer  make  our  accustomed  borings ; 
the  water  prevents  us  from  examining  whether  the  layer  we 
have  traced  from  end  to  end  of  the  land  goes  on  beneath 
it  to  rejoin  the  other  continent.  In  five  places,  on  the  ter- 
ritory of  the  five  senses,  we  have  attempted  to  step  over  the 
ordinary  bounds  ;  with  respect  to  the  sensations  of  sight  and 
hearing,  we  have  pushed  on  to  a  considerable  distance ;  with 
those  of  taste  and  smell,  some  advance  has  been  made  ;  and 
we  see  that,  later  on,  a  similar  one  may  be  accomplished  with 
sensations  of  touch. — From  all  these  indications,  we  have  con- 
cluded that  the  sensations  of  each  sense,  and  probably  those  of 
the  different  senses,  though  apparently  differing  inequality,  dif- 


OF  MENTAL  EVENTS.  [BOOK  IV. 

fer  in  quantity  only,  that  the  same  elementary  sensations  may, 
by  their  differences  of  number,  intensity,  and  proximity,  make 
up  whole  sensations  which  consciousness  pronounces  irreduci 
ble  to  one  another,  and  which  therefore,  different  as  they  may 
apparently  be,  probably  comprise  one  and  the  same  fact,  a 
kind  of  primitive  rock  whose  different  aspects  are  owing  to 
the  different  depths  of  the  water  covering  it.  We  have  further 
proved  that  this  rock,  though  invisible  at  a  certain  depth  of 
water,  still  subsists  there  and  is  indefinitely  prolonged,  since 
at  a  certain  degree  of  brevity  or  weakness,  the  sensation,  though 
imperceptible  to  consciousness,  is  nevertheless  real,  and  is 
found  to  be  made  up  of  infinitesimal  elements.  Beyond,  then, 
the  psychological  world  observable  by  consciousness,  there 
extends  to  infinity  a  pyschological  world  to  which  conscious- 
ness does  not  attain.  Here  then  we  part  from  consciousness, 
which  can  teach  us  nothing  further,  and  pass  to  the  other  con- 
tinent, to  see  if  anatomy  and  physiology  will  not,  on  their  side, 
indicate  to  us  some  projecting  rock,  connecting  itself  with  ours, 
beneath  the  obscure  sea  which  appears  forever  to  separate  the 
countries. 

II.  Let  us  look  then  for  the  physical  facts  on  which  our 
mental  events  depend,  and  first,  for  the  conditions  of  sensa- 
tion. These  are  direct  or  indirect,  and  make  up  a  chain 
whose  earlier  links  act  only  when  the  last  one  is  affected. 

Let  us  trace  this  chain.  In  the  first  place,  there  is  the 
physical  external  event,  the  undulation  of  air  or  ether,  the 
chemical  action  of  the  liquid  or  volatile  body,  the  mechanical 
pressure,  the  change  of  temperature,  which  by  dilatation  or 
contraction  of  the  parts  arrives  at  affecting  the  nerve.  This 
condition  is  plainly  but  an  accessory  and  distant  one.  Though 
the  nerve  be  so  constructed  as  to  translate  more  specially  ex- 
ternal movements  of  a  certain  type,  it  has  its  own  type  of 
action  ;  it  is  a  spring  which,  however  it  be  set  going,  works  in 
one  way.* — The  optic  nerve  when  excited  gives  no  other 
sensations  than  those  of  light;  its  various  stimuli  result  in 
the  same  effect.  An  undulation  of  ether  strikes  it,  and  we 
have  sensations  of  color.  It  is  excited  by  compressing  the 


*  Mueller,  "  Physiology  "  (tr.  Baly),  ii.  1069. 


CHAP.  I.]     FUNCTIONS  OF  THE  NERVOUS  CENTRES.  145 

eyeball,  and  we  see  brilliant  circles,  which  are  termed  phos- 
phenes.  It  is  divided  in  a  surgical  operation,  and  at  the  mo- 
ment of  its  section,  the  patient  sees  sudden  large  bodies  of 
light.  An  electric  current  is  applied  to  it,  and  we  see  vivid 
flashes  of  light.  Digitalis  is  absorbed  into  the  blood,  and  the 
blood  so  altered  excites  in  it  sensations  of  flickering  light. — So 
again  the  acoustic  nerve  gives  no  other  sensations  than  those 
of  sound,*  whatever  be  the  external  event  which  sets  it  in  op- 
eration, whether  an  undulation  of  air,  electricity,  irritation 
of  the  blood,  or  a  narcotic  absorbed  into  the  blood. — So  it  is 
with  the  other  senses,  and  notably  with  that  of  touch.  The 
tactile  nerves  serve  better  than  any  others  to  prove  this  ;  for 
they  are  excited  by  a  number  of  different  external  events, 
mechanical  contact  or  pressure,  the  chemical  action  of  caustics, 
of  the  air,  and  blood,  change  of  temperature,  undulations  of 
air  or  ether,  section  with  the  bistoury  ;  their  action  invariably 
results  in  a  sensation  of  contact,  or  pressure,  of  temperature, 
or  of  pure  pain. 

Not  only  has  each  kind  of  nerve  its  special  action,  but  the 
action  of  each  kind  is  different.  The  external  event  may  be 
the  same,  but,  if  it  sets  in  motion  nerves  of  different  kinds, 
the  sensations  excited  will  be  different.  The  same  electric 
action  arouses,  according  to  the  nerve  it  sets  in  action,  here  a 
sensation  of  light,  there  of  sound,  elsewhere  again  one  of 
shock  or  of  pricking.  The  same  violent  blow  arouses  a  sensa- 
tion of  pressure  and  pain  through  the  tactile  nerves,  of  light 
through  the  medium  of  the  optic  nerve,  of  sound  through  the 
medium  of  the  acoustic  nerve.  The  same  narcotic,  intro- 
duced into  the  blood,  arouses  flashings  when  acting  on  the 
optic  nerve,  ringings  when  acting  on  the  acoustic  nerve,  for- 
mication when  acting  on  the  tactile  nerves. — Thus  each  dis- 
tinct kind  of  nerve  has  its  individual  and  distinct  mode  of 
action. 

Hence  it  follows  that  all  external  excitants  may  be  absent ; 
if  the  nerve  enters  into  action  of  itself,  we  should  have  the 


*  That  is,  in  the  Limacean   branch.     See  Flourens's  experiments.     On   the 
other  hand,  it  is  sensible  to  pain  in  the  vestibular  branch  ;  this  then  belongs  to  the 
group  of  tactile  nerves. 
IO 


146  OF  MENTAL  EVENTS.  [BOOK  IV. 

same  sensation  in  their  absence  as  in  their  presence. — And,  in 
fact,  this  is  what  happens :  we  experience  without  their  con- 
currence a  number  of  sensations  which  we  term  subjective  or 
consecutive.  They  are  especially  numerous  in  the  case  of 
sight ;  the  excitation  of  the  optic  nerve,  and  the  consequent 
sensation  of  colors  or  of  light,  lasts  after  the  undulation  of 
ether  has  ceased  to  impress  the  retina  ;  in  such  a  case  we  con- 
tinue to  see,  with  closed  eyelids,  or  with  the  eye  turned  in  a 
different  direction,  the  object  we  were  first  looking  at ;  accord- 
ing to  the  circumstances,  the  object  is  uncolored  or  colored, 
of  persistent  or  of  changing  color ;  and  these  illusions  are 
subject  to  known  laws  by  which  a  multitude  of  singular  facts 
are  explicable.* — The  same  kinds  of  spontaneous  sensations 
are  found  in  the  sense  of  hearing.  "  Such  are  the  ringings 
and  buzzings  in  the  ears  heard  by  persons  of  delicate  nerves 
and  patients  with  disease  of  the  auditory  nerve  ;  such,  too,  is 
the  noise  heard  in  the  ears  for  some  time  after  a  long  journey 
in  a  noisy  vehicle."f  Subjective  sensations  of  taste  and  smell 
are  not  so  easy  to  detect.  If  some  patients  are  continually 
complaining  of  smelling  fetid  odors,  it  is  not  certain  that  the 
origin  of  their  sensation  is  in  the  nerve  itself;  it  may  possibly 
be  found  in  the  nervous  centres. — But  there  is  nothing  more 
common  than  spontaneous  action  of  the  nerves  of  touch ;  it 
is  enough  to  mention  neuralgia,  strictly  so  called  ;  the  simple 
action  of  the  nerve,  in  the  absence  of  all  appreciable  excitants, 
arouses,  maintains,  and  then  revives  the  keenest  and  most 
various  sensations  of  pain. 

This  is  why,  if  the  state  of  the  nerve  changes,  though  the 
excitant  continue  the  same,  the  sensation  changes  in  de- 
gree, or  even  in  quality.  For  instance,  if  the  nerve  has  be- 
come unduly  excitable,  the  least  stimulus  develops  an  ex- 
treme action,  and  the  sensation  is  of  terrible  intensity ;  this 
is  the  case  with  the  unfortunate  patients  who  suffer  from  hy- 
peraesthesia  of  the  optic,  acoustic,  or  tactile  nerves.  If,  on  the 
other  hand,  the  nerve  has  become  less  excitable,  or  has  ceased 
to  be  excitable  at  all,  the  strongest  stimuli  will  only  arouse  in 


*  Helmholtz,  "  Handbuch  der  Physiologischen  Optik."     2me  partie,  §§  22-25 
f  Mueller  (tr.  Baly),  ii.  1072,  1210,  1310. 


CHAP.  I.]      FUNCTIONS  OF  THE  NERVOUS  CENTRES.  i^j 

it  weak  or  imperceptible  sensations ;  this  happens  when  the 
nerve  is  divided,  tied,  benumbed  with  cold,  or  paralyzed  by 
illness.  Finally,  if  the  nerve  has  become  excitable  in  a  differ- 
ent way,  its  action,  though  induced  by  the  same  stimulus,  is 
different,  and  the  sensation  is  no  longer  the  same  ;  in  indiges- 
tion or  fever,  all  kinds  of  food  have  an  earthy  or  bitter  taste. 
—In  short,  the  direct  condition  of  the  sensation  is  the  action 
or  molecular  motion  of  the  nerve ;  neither  external  events  nor 
the  other  internal  events  of  the  living  body  matter  much  ;  they 
only  act  by  means  of  the  movement  they  excite ;  in  them- 
selves, they  do  nothing  ;  they  may  be  dispensed  with.  If  the 
action  of  the  nerve  were  always  spontaneous,  as  it  sometimes 
is  ;  if  this  action  were  still  produced  according  to  the  ordinary 
order  and  degree,  the  external  world,  and  all  within  us  ex- 
cepting the  nervous  system,  might  be  annihilated  ;  we  should 
still  have  the  same  sensations,  and  consequently  the  same 
images  and  the  same  ideas.  Let  us  look,  then,  more  closely 
into  this  nervous  action,  since  there  is  no  sensation  without 
it,  and  since  it  is  sufficient  of  itself  to  excite  sensation. 

III.  When  a  sensitive  nerve  commences  to  act,  a  molecular 
movement  is  propagated  through  its  whole  course  till  it  reach- 
es the  nervous  centres.*  The  nerve  is  a  conductor,  just  as 
the  air  which  transmits  the  oscillations  of  a  vibrating  string, 
or  the  iron  wire  which  transmits  electric  action.  Two  exper- 
iments prove  this. — If  it  is  compressed,  tied  or  cut  at  any  point 
between  the  nervous  centres  and  the  spot  excited,  there  is  no 
longer  any  sensation ;  in  this  case  the  nervous  centres  are  in 
tact,  the  terminal  extremity  of  the  nerve  acts  as  before ;  the 
central  part  of  the  nerve,  then,  is  what  has  ceased  to  act ;  there- 
fore, it  was  previously  acting;  therefore  when,  in  consequence 
of  a  terminal  excitation,  a  sensation  is  produced,  the  nerve 
has  acted  in  all  its  segments  and  through  all  its  course. — On 
the  other  hand,  in  all  parts  of  its  course,  this  action  results  in 
the  same  effect.f  At  whatever  point  it  may  be  irritated,  the 


*  This  movement  is  produced  in  the  central  filament  of  the  nerve,  termed  the 
axis-cylinder.  It  is  the  only  essential  part  of  the  nerve.  Vulpian,  "  Lemons  sur  la 
Physiologic  du  Systeme  Nerveux.,"  p.  55. 

\  Mueller,  "  Physiology"  (tr.  Baly),  i.  636.  Of  the  laws  of  action  of  sensitive 
nerves. 


I48  OF  MENTAL  EVENTS.  [BOOK  IV. 

final  sensation  is  the  same.     This  extends  so  far  that  some- 
times  our   associated   images  localize  the  sensation  in  parts 
which  are  insensible  or  absent.     "  There  are  kinds  of  paralysis 
in  which  the  limbs  are  absolutely  insensible  to  external  irrita- 
tions, though  the  severest  pains  are  felt  there."     The  fact  is, 
the  nerves  which  supply  these  limbs,  though  insensible  at  their 
extremities,  are  still  irritable  and  irritated  in  the  higher  parts 
of  their  course.     For  the  same  reason,  any  section,  compres- 
sion or  irritation  of  a  nervous  trunk  exites  a  sensation  which  ap- 
pears to  be  situated  in  the  parts  to  which  the  branches  and 
terminal  fibres  of  the  trunk  lead.     If  the  arm  be  compressed 
with  a  tourniquet  till  it  is  insensible  to  excitations  from  with- 
out, and  if  the  nervous  trunk  between  the  two  bones  of  the 
elbow  be  then  pressed,  a  keen  sensation  will  be  felt  similar  to 
that  of  an  electric  shock,  and  this  sensation  appears  to  be  situ- 
ated in  the  part  whose  nerves  are  benumbed.     Every  one  has 
heard  of  the  illusions  of  persons  who  have  lost  limbs.     "  These 
illusions  persist  and  retain  the  same  intensity  through  the 
whole  of  life  ;  we  may  convince  ourselves  of  this  by  question- 
ing persons  who  have  suffered  an  amputation  a  long  time  after 
they  have  undergone  the  operation.     They  are  most  vivid  at 
the  time  of  the  inflammation  of  the  stump  and  nervous  trunks ; 
the  patients  then  complain  of  very  severe  pains  throughout 
the  limb  which  they  have  lost.     After  the  cure  there  frequent- 
ly remains  for  life  a  feeling  of  formication,  or  even  of  pain,  seat- 
ed apparently  in  the  non-existent  external  parts.     These  sen- 
sations are  not  vague,  for  the  patient  feels  pains  or  pricking  in 
some  particular  spot,  the  heel,  the  sole,  or  the  back  of  the  foot, 
the  skin,  etc.     They  end  by  becoming  accustomed  to  it,  and 
finally  cease  to  perceive  it ;  still,  if  attention  be  called  to  it, 
the  sensation  reappears,  and  is  often  felt  very  distinctly  in 
the  heel,  the  fingers,  the  sole  of  the  foot,  the  hand,"  etc.     In 
many  cases,  after  seven,  twelve,  or  even  twenty  years,  the  sen- 
sation is  as  plain  as  on  the  first  day. — We  see  that  for  the 
purpose  of  exciting  the  sensation,  the  action  of  nerve  is  itself 
accessory  only ;  it  is  only  a  medium ;  if  the  molecular  move- 
ment which  is  propagated  along  its  course  is  effective,  it  is 
simply  because  it  excites  another  molecular  movement  in  the 
nervous  centres ;  just  as  the  electric  action  that  runs  along 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  i^g 

the  telegraph  wire  has  no  importance  till  it  arrives  at  its  des- 
tination and  moves  the  needle  of  the  dial-plate. 

What  is  this  molecular  movement  which  is  propagated 
throughout  the  conducting  nerve  ?  We  cannot  tell ;  all  we 
know  are  some  of  its  characteristics.*  We  prove  that  in  the 
sensitive  nerves,  though  its  usual  course  is  in  the  direction  of 
the  centres,  it  may  also  be  directed  towards  the  extremities. 
If  we  engraft  the  end  of  a  rat's  tail  into  the  skin  of  its  back, 
and  then,  when  the  grafting  process  is  completed,  cut  the  bas- 
ilary  portion  of  the  tail  about  a  centimetre  from  the  root ; 
after  some  months,  if  the  grafted  tail  be  pinched,  the  animal 
feels  it,  and  turns  round  to  bite  ;  the  irritation  of  the  nerve, 
which,  before  the  operation,  acted  in  a  centripetal  direction, 
now  acts  in  a  centrifugal  one. — We  can  further  prove  that  the 
molecular  movement  is  the  same  in  a  motor  nerve  and  in  a 
nerve  of  sensation.  For  if  we  unite  end  to  end  the  fibres  of 
a  motor  nerve,  as  the  hypoglossal,  with  those  of  a  sensitive 
nerve,  like  the  lingual,  on  the  one  hand,  the  irritation  of  the 
sensitive  nerve  is  visibly  propagated  along  the  motor  nerve, 
and  produces  muscular  contractions ;  while,  on  the  other  hand, 
it  is  very  probable  that  the  irritation  of  the  motor  nerve  is 
propagated  along  the  sensitive  nerve,  and  excites  pain. — We 
finally  establish  that  "  every  excitation  applied  to  any  part  of 
the  length  of  a  nervous  fibre  is  immediately  and  simultaneously 
transmitted  in  two  directions,  centripetal  and  centrifugal,' 
and  we  have  some  indications  as  to  the  velocity  of  this  trans- 
mission.f— The  conclusion  from  all  this  is,  that  "  the  intimate 
phenomena  caused  by  an  excitation  of  the  nervous  fibres  are 
certainly  identical,  whether  those  fibres  are  motor,  sensitive, 
or  sympathetic."  If  the  final  effect  be  different,  it  arises  from 
the  different  ramifications  of  the  nervous  fibres,  some  being  in 
connection  with  muscles,  and  others,  with  particular  parts  of 
the  nervous  centres  ;  just  as  similar  wires,  which  are  the  thea- 
tre of  similar  electrical  phenomena,  produce  according  to  the 

*  Vulpian,  op.  cit.,  102,  Experiments  of  Helmholtz,  ib.,  283  ;  of  Bert,  ib.,  287  ; 
of  Philipeaux  and  Vulpian,  ib.,  290. 

\  According  to  the  most  recent  experiments,  it  is  twenty-nine  metres  a  second 
in  the  nerves  of  the  human  body.  It  varies  with  the  surrounding  temperature, 
and  is  not  uniform  throughout  the  length  of  the  nerve. 


jijO  OF  MENTAL  EVENTS.  [BOOK  IV. 

apparatus  they  are  connected  with,  sometimes  the  ring  of  a 
bell,  sometimes  the  displacement  of  a  needle,  sometimes  the 
impact  of  a  handle. 

Hence  it  follows  that  the  immediate  condition  of  the  sen- 
sations found  in  the  nervous  centres;  where  there  is  pro- 
duced a  molecular  movement  of  unknown  nature,  without 
which  the  sensation  cannot  arise,  and  which  is  of  itself  sufficient 
to  give  rise  to  it.  And  this,  in  fact,  is  what  happens  in  very 
many  cases.  Many  sensations  arise  in  us  without  the  inter- 
vention of  the  nerves,  and  by  the  simple  excitation  of  the 
nervous  centres.  Such  are  hallucinations,  strictly  so  called,  of 
which  we  have  seen  numerous  examples,*  and,  in  which  cases, 
we  can,  on  most  occasions,  neither  prove  nor  conjecture  the 
existence  of  any  irritation  of  the  extremity  or  any  portion  of 
the  course  of  the  nerve. — I  have  described  the  visions  which 
precede  sleep,  and  which  any  one  may  observe  in  himself;  in 
such  a  case,  we  close  our  eyes,  we  discard  all  excitation  from 
without,  we  pacify  all  the  nerves,  and,  as  might  be  expected, 
in  the  universal  stillness  of  all  the  conductors  which  usually 
set  the  brain  in  action,  our  vague  and  feeble  images  become 
intense  and  clear ;  they  are  turned  into  sensations  ;  we  dream, 
we  see  absent  objects.  Excepting  in  the  absence  of  objects 
and  the  inaction  of  the  nerves,  our  state  is  the  same  then  as 
in  the  cases  of  ordinary  sensation  ;  the  brain  is  then  acting 
as  in  the  case  of  ordinary  sensation ;  and  it  alone  is  acting, 
owing  to  the  absence  of  objects  and  the  inactivity  of  the  nerves. 
— When  it  is  excited  directly  and  alone,  hallucinations  are 
produced,  that  is  to  say,  spontaneous  sensations  with  their  as- 
sociated images  ;  and  this  is  what  happens  when  the  brain  is 
inflamed,  or  irritated  by  haschich. — Besides,  medical  observ- 
ers have  recorded  many  instances  of  patients  some  of  whose 
nerves  have  been  more  or  less  completely  destroyed,  though 
the  hallucinations  corresponding  to  these  nerves  have  been 
perfect.f  Esquirol  mentions  among  other  cases  that  of  "  a 
Jewess,  thirty-eight  years  old,  blind  and  insane,  who  never- 


*  Book  ii.  chap.  i. 

f  See  Griesinger,  "  Traite  des  Maladies  Mentales,"  101-5,  for  numerous  exam- 
ples. 


CHAP.  I.]      FUNCTIONS  OF   THE  NERVOUS  CENTRES.  i$i 

theless  saw  the  most  extraordinary  objects.  She  died  sudden- 
ly ;  I  found  the  optic  nerves  atrophied  from  their  point  of  inter- 
section to  the  points  where  they  enter  the  eyeballs ;  in  this 
case  the  transmission  of  impressions  was  clearly  impossible." 
— "  Two  persons  had  each  of  them  lost  an  eye  by  phthisis  of  ' 
the  eyeball,  and  in  their  cases  hallucinations  were  produced 
as  readily  on  the  side  on  which  the  eye  was  lost  as  on  that 
of  the  sound  eye." — "  We  have  at  present  in  the  Salpetriere," 
says  Esquirol,  "  two  women  who  are  absolutely  deaf,  and  who 
have  no  other  delusion  than  that  of  hearing  the  voices  of  dif- 
ferent persons,  with  whom  they  dispute  night  and  day," — 
Strictly  it  might  be  objected  that  in  these  instances  the  cen- 
tral and  as  yet  intact  portion  of  the  nerve  is  the  starting-point 
of  the  irritation  ;  but  this  is  not  probable  ;  the  hallucination 
is  too  systematic  ;  if  it  proceeded  from  the  nerve,  it  would  be 
requisite  that  its  different  fibres  should  enter  into  action  in 
the  complex  order  and  with  the  exact  degree  which  an  exter- 
nal excitant  could  alone  impose  on  them.  "  A  direct  irrita- 
tion," says  Griesinger, "  may  certainly  occasion  luminous  patch- 
es, globes  of  flame,  and  colored  figures  in  the  retina,  but  not 
complex  forms,  such  as  houses,  men,  trees  ;  it  may  determine 
buzzings  and  noises,  loud  or  otherwise,  in  the  ear,  but  not 
actual  words  or  tunes." — The  distinction  is  still  more  clearly 
marked  in  the  hallucinations  following  the  use  of  the  micro- 
scope ;  the  details  of  which  I  give  from  a  letter  written  me  by 
one  of  our  most  distinguished  micrographists,  M.  Robin.  "  I 
have  remarked,"  says  he,  "  that  after  having  looked  through 
a  microscope  for  some  time,  and  especially  when  I  have  been 
aided  by  a  strong  light,  the  figures  of  the  objects  observed 
persist  when  I  close  my  eyes. — They  still  persist  whether  I 
direct  my  eyes  on  the  mahogany  table  holding  my  instruments, 
or  on  my  drawing-board,  which  is  of  a  grayish-blue,  or  on  my 
drawing-paper. — They  persist  for  about  two  or  three  minutes, 
oscillating  about  in  a  narrow  circle  ;  after  diminishing  in  size 
and  then  disappearing  they  reappear,  though  paler;  after 
two  or  three  reappearances,  more  and  more  faint,  they  cease 
to  reappear. — They  disappear  more  readily  when  I  rest  my 
eyes  on  a  white  paper  than  when  I  turn  or  rest  them  on  my 
table,  which  is  of  dark  mahogany. — I  see  them  of  a  grayish 


!$2  OF  MENTAL  EVENTS.  [BOOK  IV. 

color,  just  as  the  images  of  objects  seen  under  the  microscope. 
These  images  are  the  shadow  of  the  objects,  projecting  itself 
on  the  retina,  which  is  brightly  lighted  up  around  them  in  the 
circular  field  of  the  microscope,  just  like  the  Chines?  sliadows 
of  the  magic  lantern"  In  my  opinion,  adds  M.  Robin,  it  is  not 
the  retina  which,  continues  and  recommences  to  act  in  the  ab- 
sence of  the  object ;  "  it  is  the  cerebral  centre  of  visual  percep- 
tion," which  having  once  acted,  recommences  two  or  three  times 
to  act  of  its  own  accord.  "  I  do  not  think  the  external  ex- 
tremities of  nerves  of  sensibility,  or  organs  of  impression,  are 
capable  of  such  spontaneous  action  as  to  transmit  the  form, 
color,  etc.,  of  an  object  to  the  perceptive  centre ;  but,  on  the 
other  hand,  the  centre  of  perception  itself  may  return  spon- 
taneously to  a  preceding  state  of  activity,  under  the  influence 
of  some  temporary  congestion  of  its  vessels,  such  as  is  pro- 
duced by  the  prolonged  use  of  the  microscope,  or  the  ingestion 
of  the  alkaloids  of  opium,  or  of  belladonna,  absinthe,"  etc.  In 
fact,  diseases  of  the  eye  with  congestion  of  the  retina,  but  un- 
accompanied by  meningitis,  do  not  recall  to  the  scene  images 
of  this  kind,  but  entirely  different  ones  ;  to  arouse  these,  there 
must  be  meningitis,  the  intoxication  of  opium  or  absinthe, 
that  is  to  say,  irritation  of  the  nervous  centres. — To  sum  up, 
irritation  of  the  nerves  and  that  of  the  nervous  centres  are 
recognizable  by  symptoms  of  marked  difference.  "  The  first, 
which  we  may  term  pseudassthesia  of  the  peripheral  extrem- 
ities, is  characterized  by  luminous  sparks  and  flashes,  by 
noises,  ticklings,"  and  other  isolated  sensations,  not  forming 
a  system  and  not  corresponding  to  any  possible  combination 
of  external  characters.  "  The  second,  which  we  may  term 
pseudaesthesia  of  the  perceptive  centres,"  is  characterized  by 
the  persistence  or  revival  of  complete  images,  like  those  of 
the  microscope — that  is  to  say,  by  hallucinations  or  spontan- 
eous and  organized  sensations  of  color  and  relief,  of  harmonized 
and  articulate  sounds,  corresponding  to  a  possible  combina- 
tion of  external  characters. 

IV.  We  have  then  finally  settled  that  the  necessary 
and  sufficient  condition  of  the  sensation  and  therefore  of 
images,  is  a  certain  action  or  molecular  movement  of  the  ner- 
vous centres,  that  is  to  say,  of  the  encephalon ;  in  fact,  all 


CHAP.  I.]    FUNCTIONS  OF   THE  NERVOUS  CENTRES.  j^ 

nerves  of  sensation  terminate  there,  either  directly,  as  is  the 
case  with  the  cranial  nerves,  or  indirectly,  as  the  rachidian 
nerves,  through  the  medium  of  the  conducting  parts  of  the  spi- 
nal marrow.* — We  must  now  inquire,  what  among  the  different 
parts  of  the  encephalon  are  those  whose  action  is  the  neces- 
sary and  sufficient  condition  of  sensation  and  of  images?  For 
this  purpose  physiologists  employ  vivisections,  and  their  exper- 
iments are  very  decisive  in  the  matter.  Let  us  first  consider 
the  pure  sensation. 

If  the  reader  will  examine  a  preparation  of  the  encepha- 
lon, or  at  all  events  the  figures  of  some  large  anatomi- 
cal atlas,  he  will  find  that  the  spinal  marrow  at  its  upper 
extremity  swells  out  into  a  bulb  termed  Medulla  Oblongata 
or  rachidian  bulb,  with  which  the  encephalon  commences. 
We  may  cut  away  from  an  animal  the  whole  encephalon 
excepting  this  bulb ;  the  animal  will  still  execute  a  number 
of  systematic  and  automatic  movements,  which  are  termed 
reflex,  and  which  are  produced  by  the  different  segments 
of  the  marrow  without  the  intervention  of  the  encephalon.f 
For  instance,  it  swallows  food,  the  muscles  of  its  face  still 
contract  in  an  expressive  manner,  it  articulates  vocal  sounds, 
and  goes  through  all  the  movements  of  respiration ;  but  it  can 
no  longer  experience  sensations  strictly  so  called.  It  utters 
cries,  but  mechanically  only ;  it  no  longer  suffers  pain.  Let 
a  transverse  section  be  made  above  the  bulb.  "  The  bulb 
and  marrow  are  then  isolated  from  the  encephalic  centre,  just 
as  if  the  brain  and  annular  protuberance  were  removed  ;  this 
is  what  I  do  to  this  rat.  I  now  pinch  its  paw ;  you  hear  a 
short  slight  cry.  I  do  so  again;  another  similar  cry.  I 
now  wound  deeply  the  rachidian  bulb ;  I  again  pinch  a  hind 
limb ;  there  are  reflex  movements,  but  there  is  no  longer  any 

cry Observe  the  character  of  the  cries  you  have  just 

heard,  they  are  re  flex  cries,  and  very  different  from  cries  indica- 
ting pain."  There  is  in  the  bulb,  as  in  the  different  segments 
of  the  marrow,  a  mechanism  capable  of  acting,  either  directly 
by  the  irritation  of  the  sensitive  nerves  it  receives,  or  indi- 


*  Brown-Sequard,  "  Journal  de  Physiologic  ;"  and  see  ante  book  iii.     chapter 
2,  p.  136.  |  Vulpian,  op.  cit.,  496,  510. 


154  OF  MENTAL  EVENTS.  [BOOK  IV. 

rectly  by  the  effect  of  the  sensations  aroused  in  the  other  parts 
of  the  encephalon.  When  the  other  parts  are  cut  away,  the 
bulb  continues  to  act,  and  the  cry  is  produced,  without  any 
sensation  having  been  excited. — Let  us  next  preserve,  not 
only  the  rachidian  bulb,  but  also  the  part  of  the  encephalon 
adjoining  it — the  Pom  Varolii  or  annular  protuberance  through 
which  the  fascia  of  the  bulb  pass,  and  remove  the  remain- 
ing parts,  that  is  to  say,  the  cerebral  lobes,  the  corpora 
striata,  the  optic  thalami,  and  the  corpora  quadrigemina. 
"  When  this  is  effected  on  dogs  and  rabbits,  they  manifest  by 
violent  agitation  and  plaintive  cries,  the  pain  they  feel  when 
the  trigeminal  nerve  is  pinched,  or  when  they  are  subjected 
to  keen  external  stimuli.  If  the  protuberance  be  then  deeply 
wounded,  there  are  no  more  cries  or  agitation,  even  under 
violent  pinchings ;  and  yet  the  circulation,  respiration,  and 
other  functions  continue  to  be  accomplished  for  some  time. 
....  I  have  repeated  M.  Longet's  experiments,  and  have 
obtained  precisely  the  same  results  as  his.  This  young  rab- 
bit has,  strictly  speaking,  no  brain,  neither  corpora  striata, 
nor  optic  thalami ;  all  there  is  left  in  its  skull  are  the  annular 
protuberance,  the  rachidian  bulb,  the  cerebellum,  and  the 
corpora  quadrigemina.*  I  pinch  its  tail  sharply ;  you  see  it 
is  at  once  violently  agitated.  I  pinch  its  ear,  its  lip  ;  similar 
agitation,  and  similar  cries.  Can  these  cries  be  considered 
as  reflex  phenomena?" — By  no  means.  "You  have  seen 
animals  from  which  the  whole  encephalon,  excepting  the  ra- 
chidian bulb,  has  been  removed;  these  animals  continued  to 
cry  when  pinched  ;  but  what  a  difference  between  their  cries 
and  those  we  hear  when  we  have  left  the  protuberance  intact ! 
In  the  first  case,  each  excitation  of  a  still  sensible  part  excited 
a  short  cry,  single  for  each  separate  excitation,  always  the  same, 
and  something  like  the  sounds  given  out  by  children's  toys 
when  pressed  in  a  certain  way — in  a  word,  deprived  of  all 
kind  of  signification.  There  we  have  the  reflex  cry.  But 


*  Other  experiments  show  that  the  cerebellum  does  not  intervene  in  sensation  ; 
the  functions  of  the  corpora  quadrigemina  will  be  presently  explained.  Mean- 
while this  experiment  may  be  considered  as  conclusive  as  if  the  cerebellum  and 
corpora  quadrigemina  had  also  been  removed. 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  155 

here,  with  this  rabbit,  what  a  difference  we  find !  When  a 
sensible  part  is  irritated  the  cry  is  not  a  short  but  a  prolonged 
one,  unmistakably  plaintive,  and,  after  a  single  excitation, 
the  animal  gives  several  successive  cries,  precisely  similar  to 
the  cries  of  pain  which  another  uninjured  rabbit  gives  when 
it  is  subjected  to  sharp  irritation."*  Hence  action  of  the 
protuberance  is  the  necessary  and  sufficient  condition  of  tac- 
tile sensations. — It  is  also  the  necessary  and  sufficient  con- 
dition of  sensations  of  hearing.  "  A  certain  call  made  with 
the  lips,  of  rough  purring  noise  like  that  of  an  angry  cat,  will 
always  startle  ah  uninjured  rat.  Now  here  is  a  rat  from 
which  the  brain,  strictly  so  called,  the  corpora  striata,  and 
the  optic  thalami  have  been  removed.  You  see  him — he  is 
very  quiet ;  I  make  the  noise  I  have  just  described,  and  the 
animal  at  once  gives  a  sudden  jump.  Every  time  I  make  a 
similar  noise  you  see  a  similar  jump.  Those  of  you  who  have 
noticed  the  effects  of  being  so  startled  upon  an  uninjured 
rat  will  recognize  that  they  are  of  precisely  the  same  charac- 
ter as  we  see  here."f  Finally,  the  action  of  the  protuber- 
ance is  also  the  necessary  and  sufficient  conditions  of  sensations 
of  taste.  "  I  have  removed  the  cerebral  lobes  from  kittens 
and  puppies;  and  on  pouring  down  their  throats  a  concentra- 
ted decoction  of  colocynth,  I  have  seen  them  go  through 
abrupt  motions  of  mastication,  and  contort  their  lips,  as  if  to 
rid  themselves  of  a  disagreeable  sensation.  The  same  move- 
ments were  observed  in  an  uninjured  animal  of  the  same 
species,  when  forced  to  swallow  the  same  bitter  decoction. ":£ 
There  is,  then,  a  special  centre,  the  protuberance,  whose  ac- 
tion is  the  necessary  and  sufficient  condition  of  many  kinds 
of  sensations. — There  are  other  similar  centres  which  perform 
the  same  office  with  respect  to  other  sensations.  For  the  sen- 
sations of  sight,  they  are  the  corpora  quadrigemina  or  bigem- 
ina.  "  Here  is  a  pigeon  whose  cerebral  lobes  are  entirely  re- 
moved, but  whose  corpora  bigemina  remain ;  when  I  sud- 
denly put  my  hand  near  it,  it  makes  a  slight  movement  of  the 
head  to  avoid  the  threatened  danger.  The  sight  then  is  re- 


*  Vulpian,  op.  citv  541.     Experiments  of  Longet.         \  Vulpin,  op.  cit,  548. 
\  Longet,  "  Traite  de  Physiologic,"  ii.  243.     Vulpian,  548. 


156  OF  MENTAL  EVENTS.  [BOOK  IV. 

tained.  We  have  here  a  phenomenon  analogous  to  that  which 
we  noticed  in  the  case  of  the  rat  deprived  of  its  cerebral  lobes, 
when  we  induced  a  sudden  jump  by  means  of  certain  sudden 
noises.  Here  again  we  have  an  example  of  sensations  with- 
out the  intervention  of  the  brain  strictly  so  called."* — If,  on 
the  other  hand,  we  leave  intact  the  cerebral  lobes,  and  injure 
or  destroy  the  corpora  quadrigemina,  the  animal  becomes 
blind,  preserving,  nevertheless,  all  its  ideas,  its  instincts,  and 
its  other  sensations.  The  corpora  quadrigemina,  then,  furnish 
by  their  action  the  sufficient  and  necessary  condition  of  visual 
sensations,  and  of  visual  sensations  only. — As  to  sensations 
of  smell,  experiments  have  not  yet  been  made  to  determine 
the  portion  of  encephalon  whose  action  is  their  necessary  and 
sufficient  condition ;  but  all  anatomical  and  physiological  anal- 
ogies lead  us  to  the  belief  that,  for  them,  as  for  the  other  four 
kinds  of  sensations,  there  is  a  centre,  distinct  from  the  cere- 
bral lobes  themselves. — When  excited  by  the  action  of  the 
sensitive  nerves,  the  cells  of  these  centres  perform  their  func- 
tions in  an  unknown  manner,  and  this  special  molecular  move- 
ment, without  which  there  is  no  sensation,  is  in  itself  sufficient 
to  arouse  the  sensation. 

V.  It  must  be  observed  that  we  have  here  been  dealing 
with  pure  sensations,  or  with  what  physiologists  call  crude 
unelaborated  sensations,  that  is  to  say,  with  sensations  un- 
provided with  the  faculty  of  spontaneous  revival,  and  there- 
fore with  the  faculties  of  being  associated,  of  forming  fixed 
groups,  and  of  furnishing  means  for  the  higher  operations  of 
intelligence.  We  must  now  look  to  another  class  of  experi- 
ments, and  here  again  the  concordance  of  physiology  with 
psychology  is  as  complete  as  unforeseen.  Psychological  an- 
alysis had  already  separated  the  functions ;  physiological  an- 
alysis separates  the  organs.  The  first  placed  on  one  side  pure 
sensations,  on  the  other  images  or  reviving  sensations ;  the 
second  puts  on  one  side  the  corpora  quadrigemina,  the  pro- 
tuberance, and  perhaps  another  ganglion,  whose  activity 
arouses  pure  sensations,  and  on  the  other  side  the  cerebral 


Vulpian,  557.    Experiments  of  Flourens  and  Longet. 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  \^>j 

lobes,  whose  action  arouses  images,  that  is  to  say,  reverber- 
ates, prolongs,  and  associates  sensations. 

If  the  reader  will  look  again  at  a  prepared  encephalon,  he 
will  see  that,  from  the  anterior  angles  of  the  annular  protu- 
berance, spring  two  large  white  columns,  called  cerebral  pe- 
duncles or  crura  cerebri,  whose  fibres  terminate  in  the  swell- 
ings called  optic  thalami  and  corpora  striata,  which  are  inter- 
mediate organs  to  the  cerebral  lobes  and  the  protuberance. 
In  fact,  other  fibres  start  from  these  organs  and  terminate  in 
the  cerebral  lobes.*  As  to  the  cerebral  lobes  themselves, 
they  constitute,  particularly  in  the  superior  animals,  the  great- 
est part  of  the  encephalon.  In  man  they  are  enormous,  and 
occupy  by  far  the  largest  part  of  the  cranium.  Comparative 
anatomy  has  already  foreshadowed  their  use  by  showing  us 
that  in  the  animal  series  their  volume  increases  at  the  same 
rate  as  intelligence ;  we  shall,  moreover,  find  that  their  most 
important  part  is  the  outer  layer,  composed  of  a  gray  sub- 
stance ;  and  it  is  a  no  less  significant  circumstance  that,  as  we 
ascend  the  zoological  scale,  this  surface  increases  much  more 
quickly  than  the  volume  owing  to  the  very  numerous  swellings 
and  anfractuosities  which  bend  it  into  folds  and  are  called 
circumvolutions.f  In  man  himself,  atrophy  of  the  cerebral 
lobes  and  absence  of  circumvolutions  are  always  accompanied 
with  idiocy ;  "  when  a  brain  is  below  a  certain  volume  and 
certain  weight,  it  must  necessarily  have  belonged  to  a,person 
affected  with  imbecility  .  .  .  ;  "  and,  in  general,  if  we  compare 
different  races  of  men,  "  the  volume  of  the  encephalon  is  in 
proportion  to  the  degree  of  intelligence." — All  these  presump- 
tions are  confirmed  by  our  operations  on  living  animals  ;  it  is 
sufficient  to  resume  the  preceding  experiments  \\  when  we 
have  removed  th-e  cerebral  lobes,  the  rest  of  the  encephalon 
being  intact,  pure  sensations  still,  as  we  have  seen,  subsist ; 
but  they  alone  subsist.  The  animal  still  experiences  crude 
sensations  of  light  by  means  of  the  corpora  quadrigemina,  crude 

*  Vulpian,  652,  following  Koelliker. 

f  Broca,  "  Sur  le  Volume  et  la  Forme  du  Cerveau,  suivant  les  individus  et  sui- 
vant  les  Races."  Paris,  1861. 

\  Vulpian,  690.  Flourens,  2me  edition,  "  Recherches  Experimentales  sur  les 
Proprietes  et  les  Fonctions  du  Systeme  Nerveux,"  24. 


j^S  OF  MENTAL  EVENTS.  [BOOK  IV 

sensations  of  pain,  contact,  sound,  and  taste,  by  means  of  the 
protuberance.  But  these  are  bare  sensations ;  they  are  not, 
as  in  the  normal  state,  accompanied  and  clothed  with  associa- 
ted images,  which  add  to  the  sensation  of  light  notions  of  the 
relief,  distance,  and  other  characters  of  the  luminous  object ; 
to  the  sensation  of  contact,  notions  of  situation,  resistance, 
and  form ;  to  the  sensation  of  sound  or  taste,  the  representa- 
tion of  a  sonorous  or  savory  body.  Much  less  then,  can  these 
isolated  sensations  arouse  the  associated. images  constituting 
memory  and  prevision,  and  through  them  judgments,  and  all 
the  assemblage  of  emotions,  desires,  fears,  and  determinations 
developed  by  the  notion  of  approaching  danger  or  of  future 
pleasure. 

Another  consequence  is  the  absence  of  instincts ;  for  in- 
stincts are  constituted  by  groups  of  images  whose  association 
is  innate.  A  beaver  shut  up  in  an  enclosure  in  the  Jardin 
des  Plantes,  who  collects  pieces  of  wood  and  mortar  to  make 
a  dam  of  which  he  has  no  need  in  Paris,  and  of  which  he  has 
need  in  America,  is  an  animal  in  whom  are  developed  a  spon- 
taneous system  of  images  ;  so,  again,  is  a  bird  who  builds  his 
nest  in  the  spring ;  at  the  sight  of  straw,  hair,  and  wool,  the 
notions  of  their  combination  and  usage  arise  in  him  without 
preliminary  experience,  without  tentative  effort,  in  a  fully 
constructed  order,  by  an  unacquired  wisdom.  It  matters 
little  whether  this  order  be,  as  with  man,  the  effect  of  a  per- 
sonal apprenticeship,  or,  as  with  the  brutes,  the  play  of  an 
hereditary  mechanism ;  it  is  invariably  an  order  of  represen- 
tations— that  is  to  say,  of  grouped  images ;  and  therefore,  if 
the  images  are  destroyed,  it  is  destroyed. 

This  is  what  happens  when  the  cerebral  lobes  are  cut 
away.  "The  animal  loses  all  its  intelligence."  Though,  with 
the  corpora  quadrigemina  and  protuberance,  it  may  have  re- 
tained crude  sensations,  it  no  longer  has  the  images  which 
by  their  association  with  crude  sensations  give  it  the  notion  of 
objects.  "  These  objects  continue  to  paint  themselves  on  the 
retina  ;  the  iris  remains  contractile,  the  optic  nerve  excitable  ; 
the  retina  remains  sensible  to  light ;  for  the  iris  contracts  or 
expands  accordingly  as  the  light  is  more  or  less  vivid ;  so  the 
eye  is  sensible.  And  still  the  animal  no  longer  sees " 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  i^g 

A  pigeon  thus  operated  on  "kept  itself  well  upright ;  it  flew 
when  thrown  in  the  air;  it  walked  when  pushed  on  from 
behind  ;  the  iris  of  its  eyes  was  very  contractile  ;  nevertheless, 
it  did  not  see  or  hear,  it  never  moved  spontaneously,  it  put 
on  all  the  attitudes  of  a  sleeping  or  drowsy  animal,  and  when 
roused  from  this  sort  of  lethargy,  assumed  the  attitude  of  an 

animal  waking  up When  I  let  it  alone,  it  remained 

calm  and  as  it  were  absorbed  ;  in  no  one  case  did  it  give  signs 
of  will.  In  short,  picture  to  yourself  an  animal  condemned 
to  perpetual  sleep,  and  deprived  of  the  faculty  of  dreaming  in 
this  sleep"  In  fact,  all  the  images  whose  irregular  concat- 
enation forms  dreams,  and  whose  regular  concatenation  forms 
the  waking  state,  were  absent ;  all  that  remained  were  some 
few  intermittent  sensations  aroused  by  the  experimenter, 
and,  accompanying  them,  the  dull  tendencies  and  involuntary 
movements  consecutive  to  them-. — A  hen  lived  ten  months 
after  a  mutilation  of  this  kind,  and  after  the  fifth  month,  was 
fat,  strong,  and  healthy ;  but  instincts,  memory,  prevision,  and 
judgment  were  gone.  "  I  left  her  fasting  on  many  occasions 
for  three  whole  days  at  a  time,  and  then  have  put  food  to 
her  n-ostrils,  have  dipped  her  beak  in  grain,  have  placed  grain 
in  the  anterior  part  of  her  beak,  plunged  her  beak  in  water, 
placed  her  on  a  heap  of  corn.  She  did  not  smell,  or  swallow, 
or  drink,  she  remained  motionless  on  the  heap  of  corn,  and 
would  assuredly  have  died  there  of  starvation  if  I  had  not  taken 
on  me  to  make  her  eat.  I  have  twenty  times  put  pebbles  instead 
of  grain  in  her  beak ;  she  swallowed  the  pebbles  as  she  had 
swallowed  the  grain.*  Finally,  when  she  met  with  an  obsta- 
cle in  her  way,  she  ran  against  it,  and  the  shock  stopped  her 
or  shook  her.  But  to  run  against  an  object  is  not  to  feel  it ; 

she  never  groped  about  or  hesitated  in  her  progress 

She  never  took  shelter,  however  inclement  might  be  the 
weather  ;  she  never  defended  herself  against  the  other  fowls ; 
she  no  longer  knew  how  to  fight  or  to  run  away;  the  ca- 
resses of  the  male  bird  were  indifferent  or  unperceived  by  her 
....  She  ceased  to  peck  with  her  bill. 


*  By  a  reflex  movement. 


OF  MENTAL  EVENTS.  [BOOK  IV. 

The  same  thing  happens  with  other  animals.*  Frogs 
have  no  longer  any  notion  of  eating  a  fly  held  to  their  mouths. 
"  The  mole  ceases  to  dig,  the  cat  remains  quiet  even  if  teased." 
All  images,  then,  fail,  and  consequently,  those  which  serve  as 
signs,  and  by  which  we  have  abstract  ideas,  also  perish.  Thus 
all  the  operations  which  pass  beyond  pure  sensation — not  only 
those  which  are  common  to  animals  with  man,  but  also  those 
which  are  special  to  man — have,  for  sufficient  and  necessary 
condition,  an  action  of  the  cerebral  lobes.  They  are,  then, 

*  Vulpian,  690.     Landry,  "  Paralysies,"  82. 

If  we  take  two  frogs,  one  uninjured  and  the  other  deprived  for  some  days  of 
its  cerebral  tubercles. 

"  Let  them  both  be  put  on  the  floor,  the  first  runs  off  at  once  and  tries  to  hide 
himself.  The  second,  after  a  leap  or  two,  becomes  motionless  and  remains  so. 
When  a  noise  is  made  near  them,  the  first  will  sometimes  turn  round  to  see  where 
it  comes  from  and  sometimes  run  away,  the  second  will  give  a  slight  start,  but 
will  not  move.  If  their  paws  are  pinched  they  will  both  jump  away,  and  struggle  if 
they  are  retained. 

Let  them  both  be  put  in  a  large  basin  of  water. 

The  uninjured  frog  goes  through  several  movements  of  swimming  and  tries  to 
hide  himself  at  the  bottom  of  the  basin.  Meanwhile,  the  movements  of  respiration 
have  entirely  ceased.  After  a  time,  it  regains  the  surface  of  the  water  in  order  to 
breathe,  and  tries  to  remain  there,  but  having  no  hold  exhausts  itself  in  its  efforts 
to  keep  there.  When  pushed  down  to  the  bottom,  it  soon  conies  up  again,  and 
if  prevented  from  doing  so,  will  attempt  to  come  up  at  another  part  of  the  basin. 
The  frog  deprived  of  its  brain  behaves  very  differently.  The  moment  it  is 
placed  in  the  basin  it  sinks  to  the  bottom  like  an  inert  mass  without  attempting 
to  swim.  Still,  when  stirred  with  a  stick,  it  goes  through  the  movements  of  swim- 
ming but  at  hazard  and  without  object,  and  then  becomes  motionless  and  sinks  to 
the  bottom.  In  its  case  the  respiratory  movements  continue  to  be  gone  through  as 
in  the  air,  with  the  single  difference  that  the  little  membranous  lid  of  the  nostrils 
is  completely  closed.  The  animal  remains  quietly  at  the  bottom  of  the  basin  with- 
out attempting  to  gain  the  surface  to  breathe,  and  without  showing  the  least  un- 
easiness. The  respiratory  movements  "  become  abrupt  and  few,  and  the  frog  dies 
suffocated  without  having  made  any  attempt  to  breathe,  and  without  appearing  to 
have  suffered. 

"  Thus  the  brainless  frog  does  not  know  how  to  suspend  respiration,  and 
would  inspire  water  if  the  lid  of  the  nostrils  did  not  close  automatically  at  the 
contact  of  the  liquid  ;  it  does  not  suffer  from  asphyxia,  is  not  aware  of  it,  and 
does  not  attempt  to  avoid  it.  Nothing,  it  seems  to  me,  can  better  show  than  this 
experiment  both  the  real  absence  of  perception,  the  absence  of  every  intellectual 
phenomenon,  and  the  absence  of  will. 

"  I  admit  with  M.  Flourens  that  the  brain  properly  so  called  is  the  seat  of  per- 
ception, volition,  and  all  intellectual  phenomena." 


CHAP.  I.]     FUNCTIONS  OF    THE  NERVOUS  CENTRES.  jgj 

attached  to  this  action  ;  they  rise,  perish,  are  altered,  acceler- 
ated and  transformed  with  it,  and  pathology  here  is  in  accord- 
ance with  vivisection. 

"  All  the  organs,"  says  Mueller,  "  with  the  exception 
of  the  brain,  may  either  pass  slowly  out  of  the  circle  of 
the  animal  economy  or  perish,  without  the  faculties  of  the 
mind  undergoing  any  alteration.  It  is  different  with  the 
brain  ;  any  cause  which  disturbs  its  action  slowly  or  sud- 
denly, affects  at  the  same  time  the  mind Inflammation 

of  the  brain  is  never  unattended  with  delirium,  and  at  a  later 
period  with  stupor ;  pressure  on  the  cerebrum,  whether  pro- 
duced by  depressed  bones,  serum,  blood  or  pus,  always  gives 
rise  to  delirium  or  stupor,  according  as  there  is  or  is  not 
irritation  with  the  pressure.  The  same  causes,  according  to 
the  seat  of  their  action,  frequently  abolish  the  power  of  vol- 
untary motion,  or  memory ;  and  when  the  pressure  is  removed, 
the  memory  frequently  returns,  and  it  has  been  observed 
that  the  chain  of  thought  was  immediately  resumed  at  the 
point  where  it  was  interrupted  by  the  injury."*  After  cerebral 
commotion  "  there  is  sometimes  complete  loss  of  intelligence. 
In  other  cases  the  patient  answers  questions  put  to  him,  but 
soon  falls  again  into  a  drowsy  state,  his  memory  is  sometimes 
entirely,  sometimes  partially  gone.  Total  forgetfulness  of  a 
foreign  language  is  one  of  the  most  usual  effects  of  this  com- 
motion  Patients  never  recollect  how  their  accident  has 

occurred  ;  if  they  have  fallen  from  horseback,  they  recollect 
perfectly  having  mounted  and  got  off,  but  never  recollect  the 
circumstances  of  their  fall.  The  effects  of  a  lesion  of  the  brain 
are  in  some  ways  analogous  to  those  brought  on  by  old  age  ;  the 
patient  preserves  the  recollection  of  recent  impressions  only, 
and  forgets  those  of  earlier  date.  .  .  .  With  some  patients, 
memory  remains  ever  after  imperfect.  ...  In  some  particu- 
lar cases  patients  are  unable  to  avail  themselves  of  the  right 
word  to  express  their  ideas,  the  judgment  is  often  impaired. "f 
— Other  injuries  indirectly  affecting  the  brain  produce  similar 
effects ;  we  know  that  people  faint  when  they  have  lost  much 
blood,  that  drunkenness  disorders  the  ideas,  that  narcotics 


*  Mueller,  op.  cit.  (tr.  Baly),  i.  817. 
f  Viclal,  "  Pathologic  Externe,"  750 — citing  Cooper. 
II 


!62  OF  MENTAL  EVENTS,  [BOOK  IV. 

produce  stupefaction,  haschich  brings  on  hallucinations,  coffee 
develops  a  liveliness  of  mind,  chloroform  and  ether  produce 
insensibility."  * — To  sum  up,  alteration  of  the  cerebral  lobes 
has,  as  a  consequence,  a  proportionate  alteration  of  our  images. 
If  the  lobes  become  unfitted  for  some  particular  system  of  ac- 
tions, some  particular  system  of  images,  and  therefore  some 
group  of  ideas  or  of  cognitions,  is  found  wanting.  If  their  ac- 
tion becomes  excessive,  images  of  a  more  intense  kind  escape 
from  the  repression  ordinarily  imposed  on  them  by  sensations, 
and  turn  into  hallucinations.  If,  in  addition  to  this  their  ac- 
tion becomes  disconcerted,  images  lose  their  ordinary  associ- 
ations, and  delirium  is  pronounced.  If  their  action  be  annul- 
led, all  images,  and  therefore  all  ideas  and  cognitions,  are  an- 
nulled ;  the  patient  falls  into  the  state  of  torpidity  and  deep 
stupor  which  we  find  caused  in  animals  by  cutting  away  these 
lobes. 

VI.  We  must  now  determine  on  what  part  of  the  cere- 
bral lobes  images  depend.  These  lobes  are  made  up  of  a 
white  substance  and  gray  cortical  matter;  and  all  inductions 
concur  in  attributing  images  to  the  action  of  the  gray  cortical 
matter.  In  fact,  the  extent  of  this  cortical  matter  is  augment- 
ed by  that  of  the  convolutions,  and  comparative  anatomy 
shows  us  that,  in  the  animal  kingdom,  intelligence  increases 
with  the  extent  of  the  convolutions.  Physiology  again  proves 
that  in  other  parts  of  the  nervous  system  the  white  substance 
is  simply  conductive. f  According  to  all  indications,  that  of 
the  brain  has  no  other  function.  "  It  is  evident  that  here,  as 
in  all  other  parts  of  the  nervous  system,  the  special  activity 
belongs  to  the  gray  substance.  Pathological  observations  are 

equally  conclusive Whilst  lesions  of  the  cerebellum, 

of  the  optic  thalami,  of  the  corpora  striata,  in  fact  of  the  white 


*  Longet,  ii.  36.  The  above  theory  may  be  verified  by  the  process  of  ether- 
ization. This  process  has  two  stages.  In  the  first,  the  animal  etherized  (dog  or 
rabbit),  loses  its  intelligence,  its  will,  its  instincts,  and  all  its  faculties  with  the 
exception  of  its  crude  sensations.  In  this  stage  there  is  etherization  of  the  cere- 
bral lobes  and  other  parts  of  the  encephalon,  but  not  of  the  protuberance  and 
bulb. — In  the  following  stage  the  animal  also  loses  its  sensations.  There  is  then 
etherization  of  the  annular  protuberance. 
f  Vulpian,  646,  669. 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  ^3 

medullary  masses  of  the  cerebral  lobes,  do  not  ordinarily  occa- 
sion any  permanent  or  clearly  marked  disturbance  of  the  intel- 
lectual functions,  extensive  alterations  of  the  gray  substance 
of  the  convolutions,  or  morbid  excitation  of  this  substance, 
necessarily  occasion  weakening  or  exaltation  of  these  functions 
according  to  the  nature  of  the  alteration  and  the  stage  at 
which  it  has  arrived.  Thus  we  can  explain  the  effects  of 
diffused  meningo-cephalitis  and  of  simple  meningitis.  The 
centre  of  cerebral  activity  being  thus  clearly  ascertained,  it 
is  not  permissible  to  doubt  that  we  have  here  the  true  starting- 
point  of  dementia  and  mania." 

This  gray  cortical  matter  is  composed  of  several  layers, 
which  are  alternately  gray  and  white. *  "  We  see  in  them 
nuclei,  and  very  many  multipolar  nervous  cells  of  small  dimen- 
sions ;  "  a  quantity  of  fibres  connect  together  different  regions 
of  the  gray  layer  of  the  same  lobe,  and  those  of  one  lobe  with 
the  other ;  other  fibres  connect  the  whole  surface  of  the  gray 
matter  with  the  corpora  striata  and  optic  thalami.  When  trans- 
mitted by  the  fibres  of  the  optic  thalami  and  corpora  striata, 
the  action,  which  in  the  corpora  quadrigemina  and  annular 
protuberance  had  aroused  a  crude  sensation,  passes  on  by  the 
fibres  of  the  white  substance  to  the  cells  of  the  cortical  matter 
of  the  cerebrum,  and  propagates  itself,  by  the  intermediary 
fibres,  from  one  point  to  another  of  the  gray  substance ;  this 
action  of  the  cortical  cells  is  the  necessary  and  sufficient  con- 
dition of  images,  and  consequently  of  all  cognitions  or  ideas. 
— The  scalpel,  the  microscope,  and  physiological  observation 
can  go  no  further  than  this  without  falling  into  hypotheses  ; 
we  can  neither  define  this  action  nor  explain  this  propagation, 
and  all  we  know  is  that  there  is  a  molecular  movement  in  the 
case.  But  vivisections  and  the  history  of  wounds  of  the  head 
here  afford  new  evidence,  which,  combined  with  the  former, 
enables  us  to  gain  a  general  view  of  the  functions  of  the  brain. 
It  is  a  repeating  and  mutiplying  organ,  in  which  all  the  differ- 
ent departments  of  the  gray  cortical  matter  fulfil  the  same 
functions. 

In  the  first  place,  "  it  is  easy  to  prove  by  instances  that 


According  to  M.  Baillarger — Vulpian,  644. 


164  OF  MENTAL  EVENTS.  [BOOK  IV. 

with  an  absence  we  may  term  complete  of  one  cerebral  hem- 
isphere, a  man  may  still  enjoy  all  his  intellectual  faculties  and 

even  all  his  external  senses This  was  the  case  with 

one  Vacquerie,  in  1821.  He  was  hemiplegic  on  the  left  side, 
but  his  intellectual  functions  were  intact.  At  the  autopsy,  a 
quantity  of  serum  was  found  filling  the  place  of  the  right  hem- 
isphere; the  cerebral  substance  on  that  side  had  disap- 
peared."*— Not  only  does  one  hemisphere  supply  the  place 
of  the  other,  but  any  one  region  of  the  brain,  if  sufficiently 
large,  may  supply  the  place  of  another  ;  the  proof  of  this  lies 
in  the  fact  that  any  portion  may  be  wanting  without  any  of 
the  mental  faculties  being  missed.f  The  disorganized  or  de- 
stroyed portion  may  belong  to  the  anterior  or  to  the  posteri- 
or lobes  of  the  brain  ;  it  is  of  little  consequence.  "  Berard 
reports  a  case  in  which  the  two  anterior  lobes  were  crushed, 
while  reason,  sensibility,  and  voluntary  movements  were  re- 
tained." "  An  officer  had  received  a  ball  that  had  entered 
one  temple  and  passed  out  at  the  other ;  the  wounded  man, 
who  died  very  suddenly  three  months  afterwards,  was  observed 
till  then,  and,  during  all  that  time,  not  only  did  he  enjoy  his 
full  intelligence,  but  showed  unusual  cheerfulness  and  sereni- 
ty in  the  intercourse  of  life."  \  After  the  battle  of  Landre- 
cies,  "  twelve  men  had  received  wounds  at  the  top  of  their 
heads,  as  large  as  the  palm  of  the  hand,  with  loss  of  substance 
of  integument,  bone,  dura  mater,  and  brain.  These  wounds 
were  occasioned  by  horizontal  sabre-cuts.  They  had  all  trav- 
elled more  than  thirty  leagues  before  their  wounds  were 
dressed,  sometimes  on  foot,  sometimes  in  wretched  cars,  and 
went  on  favorably  till  the  seventeenth  day.  They  preserved 
their  appetite,  their  strength,  and  even  their  martial  appear- 


*  Longet,  "  Anatomic  and  Physiologic  du  Systeme  Nerveux,"  666,  669.  And 
see  Vulpian,  707.  The  same  result  is  observed  in  pigeons  when  one  hemisphere 
has  been  removed.  They  preserve  or  regain  all  their  faculties. 

\  Longet,  ibid.     Vulpian,  711. 

\  See  "  Bulletin  de  1' Academic  de  Medecine,"  x.  6,  for  an  analogous  case  of  a 
child  four  years  and  a  half  old,  through  both  of  whose  temples  a  ball  had  passed, 
and  who  nevertheless  lived  twenty-six  days,  enjoying  the  whole  of  its  intellectual 
faculties,  with  complete  memory,  sound  judgment,  and  with  its  character  unaf- 
fected by  the  injury. 


CHAP.  I.]      FUNCTIONS  OF   THE  NERVOUS  CENTRES.  165 

ance."  *  ....  Such,  again,  is  the  case  of  the  dragoon  men- 
tioned by  Lamotte,  who  "  had  lost  by  a  sabre-cut  a  piece  of 
the  right  parietal  bone  two  inches  long,  and  three  or  four  inches 
of  the  left  parietal  bone,  down  nearly  to  the  ear.  This  wound, 
which  comprised  not  only  the  membranes  of  the  brain  but  the 
longitudinal  sinus  and  the  brain  itself,  was  followed  by  syncope, 
consequent  on  the  loss  of  blood,  but  gave  rise  to  no  serious 
ill  effects,!  and  was  cured  in  two  months  and  a  half.  Lamotte 
is  not  the  only  one  who  has  observed  cases  of  this  kind,  for 
they  are  not  very  uncommon." — All  the  mutilations  practised 
on  animals  lead  to  the  same  conclusion.  "  We  may  remove 
a  considerable  portion  of  the  cerebral  lobes,  either  in  front  or 
behind,  above  or  below,  without  their  functions  being  lost. 
A  very  small  portion,  then,  of  these  lobes  is  sufficient  for  the 
exercise  of  their  functions.  In  proportion  as  the  removal  goes 
on,  all  the  functions  are  weakened  and  gradually  become  ex- 
tinct, and,  when  certain  limits  are  passed,  they  become  actu- 
ally extinct Whenever  one  perception  is  lost,  all  are 

lost;    whenever  one  faculty  disappears,  they  all  disappear 

Provided  the  loss  of  substance  occasioned  to   the 

cerebral  lobes  does  not  exceed  certain  limits,  these  lobes  re- 
gain after  a  time  the  exercise  of  their  functions ;  when  these 
first  limits  are  passed,  the  functions  are  but  imperfectly  re- 
covered, and,  when  the  new  limits  are  also  passed,  the  func- 
tions are  not  recovered  at  all.  In  short,  as  soon  as  one  per- 
ception returns,  they  all  return,  and  as  soon  as  one  faculty 

*  Nelaton,  "  Pathologic  Externe,"  iii.  572. — Vidal,  "  Pathologic  Externe," 
ii.  744. 

f  Cf.  Karl  Vogt,  "  Lecons  sur  1'Homme,"  127. 

"  If  we  gradually,  layer  by  layer,  remove  the  cerebral  lobes  in  an  animal,  the 
different  phenomena  of  increasing  stupidity  become  more  and  more  evident,  with- 
out our  being  able  to  determine  a  special  action  in  any  one  direction. — The  re- 
moval of  half  the  brain  seems  to  have  no  appreciable  influence,  which  shows  that, 
for  some  time  at  least,  the  other  entire  half  is  able  to  supply  the  place  of  the  miss- 
ing half.  Still,  we  observe  that  the  functions  exhaust  themselves  more  quickly 
than  when  the  brain  is  entire,  which  shows  that  the  operation  influences  the  quan- 
tity, not  the  quality,  of  the  manifestation 3  of  the  organ.  Several  observations  have 
been  collected  of  men  who,  after  deep  lateral  wounds  of  the  head,  followed  by  loss 
of  cerebral  substance,  have  experienced  no  diminution  of  their  faculties,  but  -were 
speedily  exhausted,  and  compelled,  after  short  intellectual  labor,  to  stop  and  abandon 
themselves  to  complete  repose  or  even  to  sleep" 


OF  MENTAL  EVENTS.  [BOOK  IV. 

reappears,  they  all  reappear."  *  A  frog,  which  had  only  a 
fragment  left  of  its  posterior  lobes,  amounting  to  about  an 
eighth  of  the  whole  brain,  had  preserved  the  appearance  of  a 
healthy  frog.  "  Five  weeks  afterwards,  a  large  fly,  with  one 
wing  removed,  was  put  into  its  basin,  as  soon  as  the  fly  was 
in  the  basin,  the  frog  changed  its  attitude,  and  seemed  to 
watch  the  inject,  and,  as  soon  as  it  came  near,  made  a 
short  jump  and  tried  to  catch  it  with  its  tongue ;  but  it 
did  not  succeed  the  first  time,  and  was  obliged  to  recom- 
mence the  movement  of  projecting  its  tongue  ;  this  time 
it  succeeded.  On  the  following  days,  other  flies  were  given 
it,  and  it  seized  them  at  the  first  attempt.  .  .  .  The  only 
alteration  observed  in  its  movements  was,  that  it  was  a  little 
less  lively ;  and  again,  it  did  not  attempt,  like  other  frogs, 

to  escape  from  the  hand  put  out  to  catch  it On  the 

contrary,  when  the  brain  is  completely  removed,  there  is  not 
the  least  attempt  on  the  part  of  the  frogs  to  take  flies  which 
are  given  them  ;  and  they  do  not  even  swallow  the  flies  till 
placed  at  the  back  of  their  mouths." — We  see  that  in  the  case 
of  the  first  frog  the  eighth  part  of  its  brain  supplied  the  place 
of  the  rest  ;  a  larger  portion  would  be  required  in  the  case  of 
a  superior  animal,  and,  when  we  come  to  the  summit  of  the 
animal  kingdom,  the  mutual  dependence  of  the  different  parts 
of  the  brain  is  much  greater.  But  the  conclusion  is  still  the 
same.  The  brain  is  a  kind  of  polypus,  whose  elements  have 
the  same  functions.  We  cannot  say  with  precision  how  many 
cells  and  fibres  are  required  to  form  one  of  these  elements ; 
but  each  of  these  elements  is  capable,  by  its  action,  of  giving 
rise  to  all  normal  images  and  all  their  associations,  and  con- 
sequently to  all  the  operations  of  the  mind. 

Having  settled  this,  we  can,  by  aid  of  psychology,  take  a 
step  in  advance.  We  know  that  all  ideas,  all  cognitions,  all 
the  operations  of  the  mind,  are  composed  of  associated  images, 
that  all  these  associations  depend  on  the  property  of  images 
to  revive,  and  that  images  themselves  are  sensations  reviving 
spontaneously.  All  this  agrees  with  the  teaching  of  physiolo- 


*  Flourens,  "  Recherches   Experimentales,"  etc.,  99. — Vulpian,  709  (Experi- 
ments on  Fowls  and  Pigeons). 


CHAP.  I.J     FUNCTIONS  OF  THE  NERVOUS  CENTRES.  \§~ 

gy.  An  action  is  produced  in  the  sensitive  centres  strictly  so 
called,  protuberance,  or  corpora  quadrigemina ;  it  there  ex- 
cites a  primary  or  crude  sensation.  An  exactly  similar  action 
is  consequently  developed  in  a  cortical  element  of  the  cerebral 
lobes,  and  there  excites  a  secondary  sensation  or  image.  The  i 
first  action  is  incapable,  and  the  second  is  capable  of  reviving 
spontaneously;  consequently  the  crude  sensation  is  incapable, 
and  the  image  is  capable  of  reviving  spontaneously.  The 
more  extensive  is  the  cortical  matter  of  the  brain,  the  more 
elements  has  it  capable  of  setting  one  another  in  action  ;  the 
more  elements  it  has  capable  of  setting  one  another  in  action, 
the  more  delicate  an  instrument  of  repetition  it  is.  The  brain, 
then,  is  the  repeater  of  the  sensitive  centres ;  such  is  its  office  ; 
and  it  will  the  better  fulfil  this  office  the  more  numerous  the 
repeaters  of  which  it  is  itself  composed. 

Here  we  perceive  the  mechanism  which  renders  possible 
the  fundamental  property  of  images — I  mean,  their  aptitude 
for  endurance  and  revival.  As  the  brain  is  made  up  of  similar 
mutually-excitable  elements,  the  action  of  the  protuberance, 
of  the  corpora  quadrigemina,  and  in  general  of  the  centres  of 
sensation,  once  repeated  by  one  of  its  elements,  is  transmitted 
in  turn  to  the  rest,  and  may  thus  revive  indefinitely.  Imagine 
a  series  of  vibrating  strings  disposed  in  such  a  way  that  the 
movement  of  the  first  is  communicated  from  string  to  string 
up  to  the  last,  and  reverts  from  this  last  to  the  first ;  the  illus- 
tration is  homely  but  clear.  Such  is  the  action  which  runs 
through  the  similar  elements  of  the  brain ;  and  thus,  in  the 
absence  of  all  external  excitation,  it  lasts  on,  being  effaced, 
reviving,  and  so  persisting  indefinitely  through  a  series  of  ex- 
tinctions and  revivals.  Such  too  is  the  image,  and  we  have 
but  to  refer  back  to  its*  history  to  see  it  endure,  become  ef- 
faced, and  reappear  in  precisely  the  same  manner. — Assuming 
now  that,  by  a  new  excitation  of  the  centres  of  sensation,  a 
different  action  is  produced  in  one  of  the  cerebral  elements ; 
according  to  the  law  of  communication,  it  must  pass  in  turn 
to  the  other  elements,  and  we  shall  have  a  different  image 
which  will  persist  like  the  first,  while  becoming  weaker  and 
stronger  by  turns.  But  the  same  cerebral  element  cannot  be 
in  two  different  states  at  the  same  time,  and  consequently 


j6S  OF  MENTAL  EVENTS,  [BOOK  IV. 

cannot  produce  two  different  actions  at  the  same  time.  The 
cerebral  elements,  then,  will  be  drawn  in  two  different  direc- 
tions, and,  as  the  two  actions  are  incompatible,  one  alone  will 
be  propagated. 

Which  of  them  will  be  propagated  ?  There  are  conditions 
which  incline  the  balance  to  the  one  side  or  the  other.  Of  the 
two  tendencies,  one  or  the  other  will  prevail. *  We  have  seen 
the  laws  which  confer  ascendancy  on  images  and  deprive  them 
of  it,  and  these  are  precisely  the  ones  which  determine  the 
propagation  of  such  or  such  a  particular  action.  Images  strive 
together  for  predominance,  and  so  cerebral  actions  strive  to- 
gether for  propagation.  At  any  given  moment  some  one  ac- 
tion will  be  propagated,  and  will  give  the  ascendancy  to  some 
image,  and  will  then  make  way  for  another  action,  which, 
propagated  in  its  turn,  brings  on  the  scene  another  image. 
Thus  images  succeed  one  another,  and  become  preponderant 
in  proportion  as  the  action  producing  them  is  propagated 
through  a  greater  number  of  elements. 

It  must  be  observed  that  this  presence  of  an  image  is 
nothing  more  than  its  preponderance ;  it  is  considerably 
stronger  than  the  others,  that  is  all ;  but  it  does  not  exclude 
the  others  ;  on  the  contrary,  they  still  persist  in  a  rudimentary 
and  latent  state ;  and  this  obscure  persistence  may  be  observed 
at  any  moment. — You  have  sung  over,  some  fifteen  or  twenty 
times  in  succession,  a  new  air  which  has  impressed  you  a  great 
deal ;  you  are  interrupted  for  some  little  household  occupa- 
tion, or  by  some  tiresome  visit ;  on  this,  another  series  of  sen- 
sations, images,  and  ideas  unrolls  itself  perforce  within  you ; 
but  the  first,  though  it  has  yielded  its  place,  has  not  been  de- 
stroyed. It  is  pushed  back,  reduced ;  it  permits  the  others 
to  occupy  the  foremost  place  and  to  obtrude  themselves  on 
the  attention ;  but  though  retired  and  driven  back  into  the 
distance  and  shade,  it  still  exists.  You  will  find  it  there  as 
soon  as  you  revert  to  it ;  it  will  spring  again  to  the  light  of 
its  own  accord  as  soon  as  the  intruders  have  gone.  The  evi- 
dence of  its  secret  persistence  lies  in  the  disturbance,  the  un- 


*  See  ante,  Book  II.  chap.  ii.  "  Laws  of  the  Revival  and  Obliteration  of  Im- 
ages." 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  ifo 

easiness,  the  dull  tendencies  which  you  have  felt  all  the  time 
and  which  its  obscure  presence  excites  in  you. — So  again, 
you  hear  news,  good  or  bad,  and  after  an  hour  you  have  ceased 
to  think  of  it ;  but  nevertheless,  after  the  hour  and  perhaps 
for  the  whole  day,  you  still  feel  an  ill-defined  pleasure  or  in- 
quietude which  you  cannot  explain  at  first  sight,  and  which 
you  do  not  understand  till  you  reflect,  and  the  recollection  of 
the  news  returns. — Among  latent  images  or  ideas,  we  must  also 
reckon  those  of  all  the  actions  we  carry  out  while  our  minds 
are  occupied  by  some  other  preponderant  image  or  idea.  For 
example,  we  follow  out  a  thought  as  we  walk  along  ;  we  follow 
the  tune  of  the  piece  we  are  playing,  all  the  while  we  are  play- 
ing it ;  we  follow  the  argument  of  an  author  while  we  are  read- 
ing him  aloud.  In  these  different  cases,  the  images  of  the 
muscular  movements  we  wish  to  accomplish  must  be  present 
to  our  minds,  since  the  muscular  movements  are  accomplished ; 
but  their  series  is  not  observed  because  another  series  is  pre- 
ponderant.— This  is  the  constant  state  of  our  minds,  a  domi- 
nant image,  in  the  full  light,  and  extended  around  it,  a  con- 
stellation of  fading  images,  growing  more  and  more  imper- 
ceptible ;  beyond  these,  a  milky  way  of  images  wholly  invisi- 
ble, of  which  we  have  no  other  consciousness  than  by  the  effect 
of  their  mass,  that  is  to  say,  by  our  general  feelings  of  gayety 
or  sadness.  Every  image  may  pass  through  all  the  different 
states  of  light  and  dimness  ;  at  a  certain  limit,  it  escapes  from 
consciousness,  but  it  is  not  therefore  extinguished,  and  we  do 
not  know  to  what  degree  of  obliteration  it  may  possibly  de- 
scend.— The  scale  of  these  degrees  descends  to  a  marvellous 
depth  ;  it  is  enough,  to  convince  one's  self  of  this,  to  observe 
the  revivals  of  images*  taking  place  after  twenty,  thirty,  and 
fifty  years'  interruption,  and  the  abnormal  reproductions  of 
transient  experiences  which  seemed  to  have  left  no  trace  be- 
hind them.  We  find  here  the*  same  law  as  in  the  case  of 
sensations  proper ;  the  image  of  which  we  are  conscious  is 
but  a  ivliole  whose  elements  may  be  infinitesimal. 

Having  determined  this,  we  conceive  the  corresponding 


*  "  Laws  of  the  Revival  and  Obliteration  of  Images."      See  for  different  in- 
stances ante,  Book  II.  chap.  ii.  pp.  76,  77. 


170  OF  MENTAL  EVENTS.  [BOOK  IV. 

cerebral  process,  and  further,  by  this  comparison,  we  under- 
stand how  there  may  be  images  within  us  of  which  we  have 
no  consciousness.  When  an  image  is  preponderant,  the 
action  corresponding  to  it  is  propagated  through  the  greater 
part  of  the  similar  cerebral  elements  ;  but  through  the  great- 
er part  only.  Without  this  vortex  are  other  elements,  in 
which  a  different  action  may  be  propagated  at  the  same  mo- 
ment, whose  whole  intensity  is  less,  since  the  number  of  its 
factors  is  smaller  ;  to  this  action  of  less  intensity  corresponds 
the  accessory  image,  of  less  intensity,  all  but  invisible  to  con- 
sciousness, and  which  we  can  only  perceive  indirectly,  in  the 
background.  Let  the  number  of  factors  again  diminish,  the 
intensity  of  the  action,  and,  therefore  the  intensity  of  the 
image  will  diminish  proportionately;  a  moment  will  arrive 
at  which  the  image  will  be  wholly  without  the  range  of  con- 
sciousijess,  and  nevertheless  still  capable  of  as  many  degrees 
of  progressive  weakening  as  the  number  of  its  factors  is  capa- 
ble of  reductions.  The  series  of  these  degrees  and  of  these 
reductions  may  be  enormous,  and  we  can  conceive  that,  in 
addition  to  secondary  and  tertiary  images,  whose  presence 
we  may  still  distinguish  or  divine,  there  are  images  again  still 
more  enfeebled,  below  these,  others  still  more  so,  and  so  on, 
till  we  come  to  those  aroused  by  the  action  of  a  single  cer- 
ebral element.  Similarly  we  can  conceive  that  the  same  im- 
age, having  been  for  a  moment  preponderant,  may  be  effaced 
by  degrees,  may  subsist  for  a  long  time  without  our  having 
had  consciousness  of  it,  then,  of  a  sudden,  to  our  great  sur- 
prise, may  reappear  in  full  light,  according  to  the  more  or 
less  extended  ascendancy  of  the  corresponding  action,  which, 
propagated  at  first  through  the  majority  of  the  cerebral  ele- 
ments, becomes  more  and  more  limited,  is  contracted  and 
grows  thinner,  then,  later  on,  reassumes  the  ascendancy  by 
the  sudden  appearance  of  some  unforeseen  sensation  which  re- 
news one  of  its  fragments. 

VII.  We  now  know  exactly  the  physical  conditions  of  our 
mental  events ;  the  condition   of  our  crude  sensations*  is  a 


*  Vulpian,  681. — "It  is  a  notion  of  extreme  importance  in  physiology  and 
philosophy,  that  in  every  complete  sensation  there  are  two  wholly  distinct  phe- 


CHAP.  I.J      FUNCTIONS  OF  THE  NERVOUS  CENTRES.  iji 

certain  action  or  molecular  movement  of  the  protuberance 
of  the  corpora  quadrigemina,  and,  in  general,  of  some  prima- 
ry centre  of  the  encephalon  ;  the  condition  of  our  images, 
ideas,  and  the  rest,  is  the  same  molecular  movement  repeated 
and  propagated  in  the  elements  of  the  gray  cortical  matter 
of  the  brain.  On  this  molecular  movement  depend  the 
events  which  we  refer  to  our  personality ;  if  the  movement 
exist,  they  exist ;  if  it  is  missing,  they  are  missing.  There  is 
no  exception  to  this  rule  ;  the  loftiest  thought,  the  most  ab- 
stract conception,  is  subject  to  it,  through  the  words  or  signs 
which  serve  as  its  foundation.  Every  idea,  voluntary  or  not, 
clear  or  obscure,  complex  or  simple,  fugitive  or  persistent, 
implies  a  determinate  molecular  movement  in  the  cerebral 
cells. — But,  besides  the  mental  events  perceptible  to  con- 
sciousness, the  molecular  movements  of  the  nervous  centres 
also  arouse  mental  events  imperceptible  to  consciousness. 
These  are  far  more  numerous  than  the  others,  and  of  the 
world  which  makes  up  our  being,  we  only  perceive  the  highest 
points,  the  lighted-up  peaks  of  a  continent  whose  lower  levels 
remain  in  the  shade.  Beneath  ordinary  sensations  are  their 
components,  that  is  to  say,  the  elementary  sensations  which 
must  be  combined  into  groups  to  reach  our  consciousness. 
By  the  side  of  ordinary  images  and  ideas,  are  their  collaterals, 
I  mean  the  latent  images  and  ideas,  which  must  take  their 
turn  of  preponderance  and  ascendancy  in  order  to  reach  con- 
sciousness. 

Having  settled  this,  we  see  the  moral  world  extending 
far  beyond  the  limits  assigned  to  it.  We  are  accustomed 
to  limit  it  to  events  of  which  we  have  consciousness ;  but 
it  is  now  plain  that  the  capacity  of  appearing  to  conscious- 
ness belongs  only  to  certain  of  these  events;  the  majority  of 
them  do  not  possess  it.  Outside  a  little  luminous  circle,  lies 
a  large  ring  of  twilight,  and  beyond  this  an  indefinite  night ; 
but  the  events  of  this  twilight,  and  this  night  are  as  real 


nomena,  so  distinct  that  they  are  seated  in  two  different  parts  of  the  nervous  sys- 
tem. The  one  is  the  sensation  strictly  so  called,  and  has  as  its  seat  the  isthmus 
of  the  encephalon,  and  in  part,  the  annular  protuberance.  The  other  is  the  in- 
tellectual elaboration  of  the  sensation,  and  takes  place  in  the  brain  properly  so 
called." 


Ij2  OF  MENTAL  EVENTS.  [BOOK  IV. 

as  those  within  the  luminous  circle.  Hence  it  follows,  that  if 
we  find  elsewhere  a  nervous  structure,  excitations,  reactions, 
in  short  all  the  accompaniments  and  the  physical  indications 
we  meet  with  in  the  mental  events  of  which  we  have  con- 
sciousness, we  shall  have  a  right  here  also  to  conclude  the 
presence  of  moral  events  to  which  consciousness  does  not 
attain. 

This  is  the  case  with  reflex  phenomena,  one  ol  the  most 
instructive  instances  physiology  presents.  There  is  in  a 
living  body  another  centre  besides  the  encephalon ;  that  is 
the  spinal  marrow ;  this  marrow,  like  the  encephalon,  com- 
prises a  gray  substance,  which,  like  that  of  the  encephalon, 
is  a  terminus  of  transmitted  excitations,  and  a  starting-point 
for  reflected  excitations.  There  is  produced  in  it,  as  in  the 
encephalon,  an  unknown  molecular  movement,  which  is 
excited  by  the  action  of  the  sensitive  nerves,  and  excites 
the  action  of  the  motor  nerves,  and  which,  according  to  all 
analogies,  arouses,  like  the  molecular  movement  of  the  brain, 
an  event  of  the  mental  order. — In  fact,  the  action  it  gives  rise 
to  in  the  motor  nerves  is  not  irregular  ;*  "  it  is  appropriate 
and  adapted  ;"  it  seems  "  intentional."  In  every  case,  it  tends 
to  an  object,  "  even  when  the  animal  is  deprived  of  its  en- 
cephalon," and  this  so  perfectly,  that  many  physiologists 
have  admitted  a  soul,  or  at  least,  "  a  perceptive  and  physical 
centre,"  in  the  segment  of  marrow  thus  cut  off. — "  Here 
is  a  Triton,  whose  head,  with  the  anterior  part  of  the  body 
and  the  two  corresponding  limbs,  have  been  removed  by  a 
transverse  section.  I  pinch  the  skin  of  the  lateral  parts  of 
the  body ;  there  is,  as  you  see,  a  movement  of  lateral  curva- 
ture of  the  body,  producing  a  concavity  of  the  irritated  side, 
and  it  is  plain  that  the  result  of  the  movement  is  to  remove 
the  irritated  part  away  from  the  object  irritating  it.  Now, 
this  is  the  precise  movement  which  we  see  in  unmutilated 

Tritons  when  subjected  to  a  similar  irritation If 

they  do  not  succeed  by  this  means,  they  attempt  to  rid 
themselves  of  the  irritating  object  by  another  plan  which 
this  mutilated  Triton  will  also  put  into  execution.  You  see, 


Vulpian  414,  et  seq. 


CHAP.  I.]      FUNCTIONS  OF   THE  NERVOUS  CENTRES.  j^ 

in  fact,  a  movement  takes  place  of  the  hind  limb  on  the 
irritated  side."  The  movements  alter  according  to  the 
point  irritated,  and  the  new  combination  of  muscular  move- 
ments is  always  one  adapted  to  avoid  the  new  cause  of 
irritation.  "All  these  movements  are  so  well  adapted  and 
natural,  that  if  the  wound  caused  by  the  decapitation  were 
not  apparent,  you  would  think  the  animal  had  undergone 
no  mutilation,  and  the  common  character  of  these  move- 
ments is  that  their  effect  is  defence  against  attacks  from  with- 
out." 

So  too,  frogs  when  beheaded,  can  still  leap  and  swim. 
Further,  "  if  we  put  a  drop  of  acetic  acid  on  the  upper  part 
of  the  thigh  of  a  decapitated  frog,  the  hind  limb  bends  in 
such  a  way  that  the  foot  rubs  against  the  irritated  part." 
The  foot  is  amputated  and  the  experiment  repeated.  "  The 
animal  begins  new  movements  to  rub  the  irritated  part ;  but 
he  cannot  reach  it,  and  after  some  movements  of  agitation, 
as  if  he  were  seeking  a  new  mode  of  accomplishing  his 
design,  he  bends  the  other  limb,  and  thus  succeeds  in  doing 
so." — These  are  the  most  salient  experiments,  and  it  will  be 
comprehended  that,  to  obtain  such  striking  facts,  we  must 
operate  on  the  lower  animals,  whose  life  is  more  tenacious, 
and  whose  parts  are  less  strictly  connected  with  one  another. 
— But  similar  ones  are  met  with  among  the  mammalia  and 
even  in  man.*  Cases  have  been  seen  "  of  anencephalous 
fcetuses,  who  cried  and  sucked  a  finger  placed  to  their 
lips.  Beyer,  being  compelled  once  to  open  the  head  of 
a  foetus  to  accomplish  a  delivery,  and  having  completely 
emptied  the  skull,  saw  the  foetus,  some  minutes  after  birth, 
give  a  cry,  breathe,  and  move  its  hands  and  feet." — With 
the  higher  animals,  if  we  suppress  the  whole  of  the  enceph- 
alon — that  is  to  say,  all  the  nervous  centres  with  which 
sensations  and  images,  strictly  so-called,  are  connected — 
the  spinal  marrow  and  bulb,  which  alone  remain,  are  still 
capable,  under  the  stimulus  of  the  sensitive  nerves,  of  ex- 
citing and  combining  movements  with  some  object  in  view, 
as  happens  with  the  posterior  limbs  of  a  frog  or  Triton. 

*  Vulpian,  396. 


OF  MENTAL  EVENTS.  [BOOK  IV. 

The  animal  still  cries,  though  without  pain,  when  its  paw  is 
pinched ;  it  swallows  food  when  placed  at  the  end  of  its 
gullet ;  it  goes  through  all  the  movements  of  respiration. 
In  our  own  cases,  sneezing,  coughing,  vomiting,  are  so 
many  systematically  complex  and  useful  movements,  excited 
without  exercise  of  will  on  our  parts,  through  the  medium 
of  the  bulb.* — In  general,  given  in  an  animal  a  segment  of 
spinal  marrow,  with  the  sensitive  nerves  terminating  in  it, 
and  the  motor  nerves  springing  from  it,  when  the  sensitive 
nerves  are  excited,  the  segment,  commencing  to  act,  will 
set  to  work  the  motor  nerves,  and  we  shall  see  muscular 
contractions.  This  may  be  readily  observed  in  eels,  sala- 
manders, and  serpents.  Landryf  observed  it  in  sucking 
pigs,  whose  spinal  marrow  he  divided  into  several  segments, 
while  leaving  the  rest  of  the  body  intact.  Animals  thus 
treated  may  live  a  long  time,  and  while  the  circulation 
subsists,  "  the  reflex  excitability  of  a  separated  portion  of 
the  marrow  may  persist  almost  indefinitely;"  it  has  been 
seen  to  last  three  months,  and  even  for  more  than  a  year. 

.  Every  segment  then  is  a  sort  of  complete  animal,  capable 
in  itself  of  being  excited  and  of  reacting,  capable  even  of  liv- 
ing in  an  isolated  state,  if,  as  is  the  case  with  the  inferior  an- 
imals, and  notably  with  the  annelidae,  the  mutual  dependence 
of  the  segments  is  not  too  great.;}: — We  should  never  come 


*  Vulpian,  423. 

f  "  Des  Paralysies,"  47.     Experiments,  6,  7,  8.     Vulpian,  432. 

\  Landry,  "  Paralysies,"  47.  The  spinal  marrow  may  be  divided  perpendicu- 
larly to  its  axis  in  two,  three,  four,  or  more  segments,  without  inducing  any  modi- 
fication of  the  phenomena  in  which  it  takes  part. — Each  one  of  these  parts,  anatomi- 
cally constituted  like  the  whole  organ,  possesses  separately  the  same  faculties.  I 
have  shown  by  experiments  9,  7,  and  8,  that  a  simple  transversal  section  of  the  mar- 
row, though  it  interrupts  its  continuity,  leaves  the  reflex  power,  the  excitability  of 
the  nerves,  the  contractility  and  nutrition  of  the  muscles,  still  subsisting,  in  all  the 

parts  whose  sensibility  and  movement  are  paralyzed Every  segment  of 

the  marrow  then  is  a  real  centre  of  innervation Thus  we  may  consider  the 

medullary  cord  as  made  up  of  a  series  of  nervous  centres  with  identical  properties, 
but  affected  nevertheless  with  different  functions  according  to  the  different  organs 

with  which  the  nerves  springing  from  it  are  connected This  would  be  in 

accordance  with  comparative  anatomy,  which  shows  that  the  marrow  becomes  grad- 
ually segmentary  as  we  descend  from  the  mammalia  to  fish,  and  from  these  to  an- 
imals still  lower  in  the  scale,  to  the  Crustacea  for  instance.  .  .  .  ." 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  ^ 

to  an  end  if  we  attempted  to  enumerate  all  the  cases  of  reflex 
action.  The  majority  of  the  muscular  movements  of  animal 
and  of  organic  life,  whether  intermittent  or  continuous,  are  ac- 
complished by  it  alone,  so  that  we  are  obliged  to  consider  all 
the  central  parts  of  the  nervous  system,  encephalon,  bulb,  spi- 
nal marrow,  as  constantly  set  in  action  by  the  play  of  sensi- 
tive nerves,  in  such  a  way  as  to  excite  the  play  of  motor 
nerves,  with  an  accompaniment  of  sensations  of  which  we  are 
or  are  not  conscious.  Whatever  be  the  portion  of  the  nerv- 
ous system  observed,  we  never  see  in  it  any  other  than  reflex 
actions  ;  they  may  be  more  or  less  complex,  but  are  always 
of  the  same  kind.  A  white  conducting  cord  conveys  an  ex- 
citation to  a  central  nucleus  of  gray  substance  ;  a  molecular 
movement  then  arises  in  this  substance,  and  thereupon  an 
excitation  is  carried  on  to  the  muscles  by  another  white  con- 
ducting cord.  These  three  movements  so  connected  con- 
stitute reflex  action ;  the  gray  substance,  wherever  it  be, 
in  spinal  marrow  protuberance,  or  cerebral  lobes,  always  acts 
in  the  same  way. 

Now,  in  the  protuberance  and  the  cerebral  lobes,  its  action 
arouses  mental  events,  all  of  the  same  kind ;  temporary  sen- 
sations or  reviving  sensations.  We  must,  then,  admit  that 
its  action  excites  everywhere  mental  events  of  an  allied  kind  ; 
and  inasmuch  as,  even  in  the  protuberance  and  lobes,  the 
greatest  part  of  these  events  are  imperceptible  to  conscious- 
ness, there  is  nothing  to  prevent  its  action  from  arousing,  in 
the  marrow,  mental  events  analogous  to  sensation,  but  now 
situated,  by  nature  not  by  accident,  beyond  the  reach  of  con- 
sciousness.— We  should  thus  have  three  degrees  in  sensation. 
In  the  highest  degree,  in  the  cerebral  lobes,  the  sensation  be- 
comes capable  of  revival,  and  is  termed  an  image.  In  the 
next  degree,  in  the  protuberance,  the  sensation,  incapable  of 
revival,  remains  simply  crude.  In  the  lowest  degree,  in  the 
marrow,  it  is  in  a  still  more  incomplete  state,  and  we  cannot 
now  define  it  exactly  from  our  having  no  consciousness  of  it, 
but  we  recognize  it  correctly  by  this  incapacity  to  appear, 
and  it  probably  resembles  those  elementary  sensations  which, 
when  separate,  amount  to  nothing  as  far  as  consciousness  is 
concerned,  and  only  make  up  an  ordinary  sensation  by  com- 


176  OF  MENTAL  EVENTS.  [BOOK  IV. 

biningwith  others  to  constitute  a  whole. — So  too  there  would 
be  three  degrees  of  complication  in  the  action  of  the  nervous 
centres.  At  the  lowest  degree,  in  the  marrow  would  arise 
fragmentary  actions  analogous  perhaps  to  those  which  excite 
elementary  sensations,  imperceptible  to  consciousness.  In 
the  next  degree,  in  the  protuberance,  these  same  actions  com- 
bine, when  transmitted,  into  a  total  action  exciting  the  ordi- 
nary total  sensation.  In  the  highest  degree,  in  the  lobes,  this 
total  action,  transmitted  a  second  time,  is  repeated  indefinite- 
ly by  a  series  of  mutually  excitable  cerebral  elements,  and 
then  excites  those  secondary  and  reviving  sensations  we  term 
images. — We  thus  conceive,  for  the  action  of  the  nervous  cen- 
tres as  for  mental  events,  three  stages  of  successive  transmis- 
sion and  elaboration,  and  we  can  thus  include  in  a  general 
view  the  reciprocal  dependence  and  the  development  of  the 
two  streams. 

They  form  two  long  series,  the  one  of  which  is  the  neces- 
sary and  sufficient  condition  of  the  other,  and  which  corre- 
pond  as  precisely  as  the  convexity  and  concavity  of  the  same 
curve.  On  the  one  side  are  the  molecular  movements  of  the 
nervous  centres ;  on  the  other  are  mental  events,  all  more  or 
less  analogous  to  sensation.  The  first  invariably  excite  the 
second,  and  the  degree  of  complication  found  in  the  one  series 
always  corresponds  to  an  equal  degree  of  complication  in  the 
other. — At  a  certain  degree,  the  second  series  may  be  known 
by  a  special  inward  process  we  term  consciousness  ;  but,  even 
when  at  this  degree,  it  generally  happens  that  the  events  of 
this  series  are  not  thus  known.- — Beneath  those  which  con- 
sciousness attains,  there  are  many  others  to  which  it  cannot  at- 
tain and  which  we  are  compelled  to  conceive  on  the  type  of 
those  we  know,  but  on  a  reduced  and  fragmentary  type,  and 
becoming  more  reduced  and  fragmentary  as  the  nervous  action 
exciting  them  becomes  more  simple. — Thus  we  see  that,  be- 
neath the  ordinary  sensations  which  we  know  by  conscious- 
ness, there  descends  an  indefinite  series  of  analogous  mental 
events,  more  and  more  imperfect  more  and  more  removed  from 
consciousness,  without  our  being  able  to  put  a  limit  to  this  se- 
ries of  increasing  degradations ;  and  this  successive  lowering 
which  has  its  counterpart  in  the  attenuation  of  the  nervous 


CHAP.  I.]     FUNCTIONS  OF   THE  NERVOUS  CENTRES.  ^7 

system,  leads  us  to  the  foot  of  the  zoological  scale,  while  con- 
necting together,  by  a  continuous  sequence  of  intermediate 
links,  the  most  rudimentary  outlines  and  highest  combinations 
of  the  nervous  system  and  the  mental  world. 
12 


OF  MENTAL  EVENTS.  [BOOK  IV. 


CHAPTER   II. 

RELATION  OF  THE  FUNCTIONS  OF  THE  NERVOUS  CENTRES 
AND  MENTAL  EVENTS. 

I.  HERE  we  have  the  great  question  of  the  physical  and 
the  moral  world,  two  worlds  which  the  most  obvious  expe- 
rience shows  to  be  inseparably  connected  together,  and  which 
their  representations  show  us  as  absolutely  irreducible  to 
one  another.  On  the  one  hand,  we  prove  that  the  second 
depends  on  the  first ;  on  the  other  hand,  we  are  unable  to 
conceive  that  it  so  depends. — Physiologists,  on  the  one  hand, 
willingly  lose  sight  of  the  second  fact,  and  tell  us  that  "  men- 
tal events  are  a  function  of  the  nervous  centres,  just  as  mus- 
cular contraction  is  a  function  of  the  muscles,  and  the  se- 
cretion of  bile,  a  function  of  the  liver."  Philosophers,  on  the 
other  hand,  willingly  lose  sight  of  the  first  fact,  and  tells  us 
that  "  mental  events  have  nothing  in  common  with  the  mo- 
lecular movements  of  the  nervous  centres,  and  appertain  to 
a  being  of  different  nature." — On  this,  cautious  lookers-on 
interpose  and  conclude  that : — "  It  is  true  that  mental  events 
and  the  molecular  movements  of  the  nervous  centres  are  in- 
separably connected  together ;  it  is  true  that  as  far  as  our 
mind  and  powers  of  conception  are  concerned  they  are  ab- 
solutely irreducible  to  one  another.  We  stop  at  this  difficulty, 
and  will  not  even  attempt  to  surmount  it ;  let  us  content 
ourselves  with  ignorance." — For  our  own  parts,  if  we  attempt 
to  make  an  advance  into  this  obscurity,  it  is  because  we  have 
already  made  several  advances.  On  the  one  hand,  we  have 
seen  that  our  most  abstract  ideas,  being  signs,  are  reduced 
to  images,  that  our  images  themselves  are  reviving  sensations, 
that  consequently  our  whole  entire  thought  is  reduced  to  sen- 
sations. The  difficulty  then  is  simplified,  and  it  is  now  a 
question  only  of  comprehending  the  connection  between  a 


CHAP.  II.]     THE  NERVOUS  CENTRES  AND  THOUGHT. 


179 


molecular  movement  and  a  sensation. — On  the  other  hand, 
we  have  seen  that  sensations,  though  apparently  simple,  are 
wholes  ;  that  these  wholes,  though  apparently  irreducible  to 
one  another,  may  be  composed  of  similar  elements  ;  that  at  a 
certain  degree  of  simplicity  these  elements  are  no  longer  per- 
ceived by  consciousness ;  that  the  sensation  is  then  a  com- 
pound of  rudimentary  events,  capable  of  indefinite  degrada- 
tions, incapable  of  coming  within  the  grasp  of  consciousness, 
but  whose  presence,  and  further,  whose  effectiveness  is  proved 
by  reflex  actions.  The  difficulty  is  thus  simplified  a  second 
time  ;  it  is  now  a  question  only  of  comprehending  the  con- 
nection between  these  events  and  a  molecular  movement. 
The  obscurity  still  remains  very  great ;  for  we  can  never 
conceive  these  events  otherwise  than  after  the  type  of  ordi- 
nary sensations,  and  between  this  conception  and  that  of  a 
movement  is  still  a  gulf.  But  we  know  that  ordinary  sensation 
is  a  compound,  that  it  differs  from  its  elements,  that  these  ele- 
ments escape  our  consciousness,  that  they  are  none  the  less 
real  and  active,  and,  in  this  deep  lower  twilight  whence  the 
sensation  arises,  we  shall  perhaps  discover  the  link  between 
the  physical  and  the  moral  world. 

II.  Let  us  begin  by  stating  the  difficulty  in  all  its  force. 
Since  mental  events  are  nothing  more  than  sensations  more 
or  less  twisted  and  transformed,  let  us  compare  a  sensation 
with  a  molecular  movement  of  the  nervous  centres.  Let  us 
take  the  sensation  of  golden  yellow,  that  of  a  musical  note 
like  lit,  that  given  by  the  emanations  of  a  lily,  by  the  taste  of 
sugar,  by  the  pain  of  a  cut,  by  tickling,  by  heat  or  cold.  The 
necessary  and  sufficient  condition  of  such  a  sensation,  is  an 
internal  movement  in  the  gray  substance  of  the  protuberance 
of  the  corpora  quadrigemina,  in  short,  of  a  centre  of  sensation  ; 
this  movement  may  be  unknown,  it  matters  little ;  whatever 
it  may  be,  it  consists  of  a  more  or  less  complex  and  extensive 
displacement  of  molecules,  and  is  nothing  more. — Now,  what 
relationship  can  we  imagine  between  this  displacement  and  a 
sensation  ?  Cells,  constituted  of  a  membrane  and  one  or 
more  nuclei,  are  strewed  in  a  granulated  substance,  a  kind  of 
flabby  pulp  or  grayish  jelly,  made  up  of  nuclei  and  of  innume- 
rable fibres ;  these  cells  ramify  into  slender  prolongations, 


l8o  OF  MENTAL   EVENTS.  [BOOK  IV. 

which  probably  connect  themselves  with  the  nervous  fibres, 
and  it  is  supposed  that  they  thereby  communicate  with  one 
another,  and  with  the  white  conductive  parts.  Study  as 
closely  as  you  will  the  anatomical  preparations  and  micro- 
graphic  plates  which  show  us  this  apparatus ;  suppose  the 
power  of  the  microscope  indefinitely  increased,  and  the  en- 
largement carried  to  a  million  or  a  thousand  million  diameters. 
Suppose  physiology  at  maturity,  and  the  theory  of  cellular 
movements  as  far  advanced  as  the  physical  theory  of  undula- 
tions ;  suppose  we  knew  the  mechanism  of  the  movement 
produced  in  the  gray  substance  during  a  sensation,  its  circuit 
from  cell  to  cell,  its  differences  according  as  it  excites  a  sen- 
sation of  sound  or  of  smell,  the  link  connecting  it  with  move- 
ments of  heat  or  electricity,  and  further,  the  mechanical  for- 
mula which  respects  the  mass,  velocity,  and  position  of  all 
the  elements  of  the  fibres  and  the  cells  at  any  time  of  their 
movement.  We  should  even  then  have  movement  only, 
and  movement,  of  whatever  kind  it  be,  rotatory,  undulatory, 
or  what  else,  has  no  resemblance  at  all  to  a  sensation  of  bit- 
ter, of  yellow,  of  cold,  or  of  pain.  We  cannot  convert  either 
of  these  two  conceptions  into  the  other,  and  consequently 
the  two  events  seem  to  be  of  absolutely  different  quality  ;  so 
that  analysis,  instead  of  filling  up  the  interval  between  them, 
seems  to  enlarge  it  to  an  infinite  extent.* 


*  Cf.  the  following  extract  from  Professor  Tyndall's  Address  to  the  British 
Association  for  the  Advancement  of  Science,  on  "  The  Physical  Forces  and 
Thought." 

"  I  can  hardly  imagine  that  any  profound  scientific  thinker,  who  has  reflected 
upon  the  subject,  exists  who  would  not  admit  the  extreme  probability  of  the  hy- 
pothesis, that  for  every  fact  of  consciousness,  whether  in  the  domain  of  sense,  of 
thought,  or  of  emotion,  a  certain  definite  molecular  condition  is  set  up  in  the 
brain  ;  that  this  relation  of  physics  to  consciousness  is  invariable,  so  that,  given 
the  state  of  the  brain,  the  corresponding  thought  or  feeling  might  be  inferred  ;  or 
given  the  thought  or  feeling,  the  corresponding  state  of  the  brain  might  be  inferred. 
But  how  inferred  ?  It  is  at  bottom  not  a  case  of  logical  inference  at  all,  but  of 
empirical  association.  You  may  reply  that  many  of  the  inferences  of  science  are  of 
this  character  ;  the  inference,  for  example,  that  an  electric  current  of  a  given  di- 
rection will  deflect  a  magnetic  needle  in  a  definite  way  ;  but  the  cases  differ  in 
this,  that  the  passage  from  the  current  to  the  needle,  if  not  demonstrable,  is  think- 
able, and  that  we  entertain  no  doubt  as  to  the  final  mechanical  solution  of  the 
problem  ;  but  the  passage  from  the  physics  of  the  brain  to  the  corresponding  facts 


.  II.]     THE  NERVOUS  CENTRES  AND  THOUGHTS.  jgi 

III.  Repulsed  in  this  direction,  we  must  turn  to  another. 
It  is  true  that  we  cannot  conceive  the  two  events  otherwise 
than  as  irreducible  to  one  another  ;  but  that  may  depend  on 
the  way  in  which  we  conceive  them  and  not  on  their  actual 
qualities  ;  their  incompatibility  is  perhaps  rather  apparent 
than  real ;  it  arises  on  our  side  and  not  on  theirs.  There 
would  be  nothing  extraordinary  in  such  an  illusion  as  this. 
As  a  general  rule  it  is  sufficient  for  a  fact  to  be  known  to  us 
in  two  different  ways,  for  us  to  conceive,  in  its,  place,  two  dif- 
ferent facts. 

Such  is  the  case  with  the  objects  we  know  by  the  senses. 
A  person  born  blind*  who  has  just  been  couched,  remains  for 
a  considerable  time  unable  to  reconcile  his  perceptions  of 
touch  with  those  of  sight.  Before  the  operation,  he  represented 
to  himself  a  china  cup  as  cold,  polished,  and  capable  of  af- 
fording to  the  hand  certain  sensations  of  resistance,  weight, 
and  form ;  when  he  sees  it  for  the  first  time,  and  it  gives  him 
the  sensation  of  a  white  patch,  he  conceives  the  white  lus- 
trous object  as  something  different  from  the  resisting,  heavy, 
cold,  polished  object.  He  would  stop  at  this,  if  he  did  not 
acquire  new  experiences ;  the  two  things  would  always  be  dif 
ferent  in  quality ;  they  would  form  two  worlds,  between  which 
there  would  be  no  communication. — And  so,  if  your  eyes  are 


of  consciousness  is  unthinkable.  Granted  that  a  definite  thought,  and  a  definite 
molecular  action  in  the  brain  occur  simultaneously  ;  we  do  not  possess  the  intel- 
lectual organ,  nor  apparently  any  rudiment  of  the  organ,  which  would  enable  us 
to  pass  by  a  process  of  reasoning  from  the  one  phenomenon  to  the  other.  They 
appear  together,  but  we  do  not  know  why.  Were  our  minds  and  senses  so  ex- 
panded, strengthened,  and  illuminated  as  to  enable  us  to  see  and  feel  the  very 
molecules  of  the  brain  ;  were  we  capable  of  following  all  their  motions,  all  their 
all  their  electric  discharges,  if  such  there  be  ;  and  were  we  intimately  acquainted 
with  the  corresponding  states  of  thought  and  feeling,  we  should  be  as  far  as  ever 
from  the  solution  of  the  problem,  '  How  are  these  physical  processes  connected 
with  the  facts  of  consciousness  ?  The  chasm  between  the  two  classes  of  phenomena 
would  still  remain  intellectually  impassable.  Let  the  consciousness  of  love,  for 
example,  be  associated  with  a  right-handed  spiral  motion  of  the  molecules  of  the 
brain,  and  the  consciousness  of  hate  with  a  left -handed  spiral  motion.  We  should 
then  know  when  love  that  the  motion  is  in  one  direction,  and  when  we  hate  that 
the  motion  is  in  the  other;  but  the  'WHY?'  would  still  remain  unanswered." — 
See  Report  xxxviii.  for  the  year  1868.  Transactions  of  the  Sections,  p.  5. 
*  See  post,  Part  II.  book  ii.  chap.  ii. 


1 82  OF  MENTAL  EVENTS.  [BooK  IV. 

shut  and  you  are  not  aware  of  what  is  going  to  happen,  and 
you  see  a  flash,  then  hear  a  sound,  and  then  feel  as  if  hit  on 
the  arm  with  a  stick  (the  experiment  may  be  tried  on  a  child 
or  an  ignorant  person),  you  will  imagine  that  you  have  been 
struck,  that  some  one  has  whistled,  and  that  a  bright  light 
has  shone  into  the  room  ;  and  yet  the  three  different  facts 
are  but  one,  the  passage  of  a  current  of  electricity. — The 
science  of  acoustics  had  to  be  constructed  to  show  that  the 
event  which  arouses  in  us,  through  the  tactile  nerves,  sensa- 
tions of  vibration  and  tickling,  is  the  same  as  that  which,  through 
the  acoustic  nerves,  gives  rise  to  sensations  of  sound.  Till 
very  recently  "  phenomena  of  heat,*  electricity,  light,  ill-de- 
fined enough  in  themselves,  were  thought  to  be  produced  by 
so  many  peculiar  agents,  fluids  possessed  of  special  activities. 
A  closer  examination  has  enabled  us  to  recognize  that  this 
conception  of  different  specific  heterogeneous  elements  has 
for  foundation  one  single  reason — namely,  that  the  percep- 
tion of  these  different  orders  of  phenomena  takes  effect  in 
general  through  different  organs,  and  by  thus  attaching 
themselves  more  specially  to  some  one  of  our  senses,  they 
necessarily  excite  special  sensations.  The  apparent  heter- 
ogeneity then  would  be  not  so  much  in  the  nature  of  the 
physical  agent  as  in  the  functions  of  the  physiological  instru- 
ment by  which  the  sensations  are  effected  ;  so  that  by  trans- 
ferring, by  an  erroneous  attribution,  these  differences  of  ap- 
pearance from  the  effect  to  the  cause,  we  should  in  reality 
have  classified  the  intermediate  phenomena  by  which  we 
have  cognizance  of  the  modifications  of  matter,  rather  than  by 
the  very  essence  of  these  modifications All  physical  phe- 
nomena, whatever  be  their  nature,  seem  to  be  at  foundation 
nothing  more  than  the  manifestations  of  one  and  the  same 
primordial  agent." — Thus,  the  conception  we  form  bears  in- 
variably a  deep  imprint  of  the  process  forming  it.  We  are 
compelled  then  to  take  count  of  this  imprint ;  and  therefore, 
when  we  find  within  us  two  ideas  which  have  entered  by 
different  routes,  we  ought  to  mistrust  the  tendency  which  in- 


*  M.  de  Senarmont.     From  a  Lecture  at  the  Ecole  Polytechnique,  cited  by 
Saigey.     "  La  Physique  Moderne,"  p,  216. 


CHAP.  II.]   THE  NERVOUS  CENTRES  AND  THOUGHTS.  i^ 

duces  us  to  assert  a  difference,  and  above  all  an  absolute  dif- 
ference, between  their  objects. 

Now  when  we  examine  closely  the  idea  of  a  sensation 
and  the  idea  of  a  molecular  movement  of  the  nervous  centres, 
we  find  that  they  enter  by  routes  not  merely  different,  but 
contrary. — The  first  comes  from  within,  without  any  inter- 
mediate ;  the  second  comes  from  without,  through  several 
intermediates. — To  represent  to  one's  self  a  sensation  is  to 
have  present  an  image  of  that  sensation,  that  is  to  say,  the 
sensation  itself  directly  repeated  and  spontaneously  reviving. 
To  represent  a  molecular  movement  of  the  nervous  centres  is 
to  have  present  images  of  the  tactile,  visual,  and  other  sensa- 
tions, which  it  would  excite  in  us  if  it  were  acting  on  our 
senses  from  without,  that  is  to  say,  to  imagine  sensations  of 
white,  of  gray,  of  flabby  consistency,  of  cellular  or  fibrous 
form,  of  small  quivering  points,  that  is,  in  fact,  if  we  go  furth- 
er, to  combine  internally  the  names  of  movement,  velocity, 
and  mass,  which  denote  collections  and  extracts  of  muscular 
and  tactile  sensations. — On  the  whole,  the  first  representa- 
tion is  equivalent  to  its  object,  the  second  to  the  group  of 
sensations  which  its  object  would  excite  in  us.  Now  we 
cannot  conceive  more  dissimilar  processes  of  formation.  In 
the  case,  just  now,  of  different  senses,  the  two  representations 
reached  us  by  two  different  roads,  but  both  were  external, 
so  that  there  was  nothing  to  prevent  their  having  some 
common  starting-point.  Here,  the  two  representations 
reach  us  by  two  opposite  roads,  one  from  within,  the  other 
from  without,  in  such  a  way  that  these  roads  are  perpetually 
divergent,  and  that  we  are  unable  to  conceive  their  having 
the  same  starting-point. — Thus  the  fundamental  opposition 
of  the  two  processes  of  formation  is  sufficient  to  explain  the 
mutual  irreducibility  of  the  two  representations.  One  and 
the  same  single  event  known  in  these  two  ways  will  appear 
double,  and,  whatever  be  the  link  which  experience  establishes 
between  its  two  manifestations,  we  shall  never  be  able  to  con- 
vert one  of  them  into  the  other.  According  as  its  represen- 
tation comes  from  without  or  within,  it  will  invariably  appear 
as  a  thing  without,  or  within,  and  we  shall  never  be  able  to 
reduce  that  which  is  without  to  that  which  is  within,  or  that 
which  is  within  to  that  which  is  without. 


184  OF  MENTAL  EVENTS.  [BooK  IV 

IV.  It  is  possible  then  that  the  sensation  and  the  internal 
movement  of  the  nervous  centres  may  be  at  bottom  one  and 
the  same  unique  event,  condemned,  by  the  two  ways  in  which 
it  is  known,  always  and  irremediably  to  appear  double. 
Another  line  of  reasoning  leads  to  a  similar  conclusion.  In 
fact,  we  have  seen  that  our  sensations  are  but  wholes,  com- 
posed of  elementary  sensations,  that  these  are  similarly  com- 
posed, and  so  on  ;  that  at  each  of  these  degrees  of  composi- 
tion the  compound  presents  itself  to  us  with  qualities  wholly 
different  from  those  of  its  elements,  that  consequently,  the 
more  simple  the  elements,  and  the  more  removed  from  the 
grasp  of  consciousness,  the  more  must  they  differ,  as  far  as 
we  are  concerned,  from  the  whole  which  is  accessible  to  con- 
sciousness, in  such  a  way  that  the  aspect  of  the  infinitesimal 
elements  at  the  foot  of  the  scale,  and  that  of  the  whole  sensa- 
tion at  the  summit  of  the  scale,  must  be  wholly  and  entirely 
different.  Now  such  is  the  aspect  of  the  molecular  move- 
ments when  compared  with  that  of  the  entire  sensation.  Con- 
sequently, there  is  nothing  to  prevent  the  molecular  move- 
ments from  being  the  infinitesimal  elements  of  the  whole  sen- 
sation.— Thus,  the  fundamental  objection  is  removed.*  If  our 
conceptions  of  the  mental  and  of  the  cerebral  event  are  irre- 
ducible to  one  another,  it  may  doubtless  depend  on  the  two 
events  being,  in  fact,  irreducible  to  one  another ;  but  it  may 
also  depend,  first,  on  the  event  which  is  single,  being  known 
to  us  in  two  directly  contrary  ways,  and,  next,  on  the  mental 
event  and  its  ultimate  elements  being  forcedly  presented  to 
us  under  absolutely  opposite  aspects. 

There  is  room  then,  and  equal  room,  for  the  two  hypo- 
theses, for  that  of  two  heterogeneous  events,  and  for  that  of 
one  and  the  same  event  known  under  two  different  aspects. 
Which  must  we  choose? — If  we  adopt  the  first  we  are  con- 
fronted with  a  link,  not  only  unexplained,  but  inexplicable. 
For,  the  two  events  being  by  nature  irreducible  to  one  anoth- 
er, form  two  worlds,  apart  and  isolated ;  we  exclude  by  hy- 
pothesis any  more  general  event  of  which  they  might  be  but 
distinct  forms  and  particular  cases ;  we  declare  beforehand 
that  their  nature  furnishes  nothing  on  which  their  reciprocal 
dependence  may  be  founded.  We  are  compelled,  then,  in 


CHAP.  II.]   THE  NERVOUS  CENTRES  AND  THOUGHTS.  Xg5 

order  to  explain  this  dependence,  to  seek  for  it  in  something 
above  their  nature,  and  therefore  above  all  nature,  for  they, 
between  them,  make  up  all  nature,  consequently,  then,  in  the 
supernatural.  So  that  we  must  call  in  aid  a  miracle,  the  in- 
tervention of  a  superior  being.  The  philosophers  of  the  sev- 
enteenth century,  Leibnitz  and  Malebranche  at  their  head, 
clearly  saw  this  consequence,  and  boldly  decided  that  there 
was  a  pre-established  harmony,  the  artificial  agreement  of 
two  independent  clocks,  an  extrinsic  adjustment  descending 
from  on  high,  a  special  decree  of  God. — Nothing  could  be  less 
conformable  to  the  methods  of  scientific  induction  :  which  ex- 
clude all  hypotheses  by  which  is  nothing  explained. — We  are 
driven  back  then  to  the  second  supposition.  And,  first,  it  is 
in  itself  as  plausible  as  the  other.  Again,  it  has  analogies 
and  numerous  precedents  in  its  favor ;  for,  like  so  many  other 
physical  and  psychological  theories,  it  takes  into  consideration 
the  influence  of  the  percipient  and  sentient  subject,  the  struct- 
ure of  the  observing  instrument,  the  effects  of  optics.  Besides 
this,  it  calls  in  no  third  cause,  no  imaginary  or  unknown  prop- 
erty;  it  is  as  little  hypothetical  as  possible.  Finally,  it  shows 
not  only  that  the  two  events  may  be  connected  with  one  anoth- 
er, but  that  they  must  always  and  necessarily  be  so  connected, 
For,  from  the  moment  they  are  reduced  to  one  single  fact, 
possessed  of  two  aspects,  they  evidently  become  like  the  front 
and  reverse  side  of  a  surface,  so  that  the  presence  or  absence 
of  the  one  will  infallibly  result  in  the  presence  or  absence  of 
the  other. — We  are  entitled  then  to  admit  that  the  cerebral 
event  and  the  mental  event  are,  at  foundation,  but  one  and 
the  same  event  under  two  aspects,  one  moral,  the  other  phys- 
ical, one  accessible  to  consciousness,  the  other  accessible  to 
the  senses. 

Now  of  the  two  ways  in  which  we  attain  to  this  event, 
the  one,  consciousness,  is  direct ;  to  know  a  sensation  by  con- 
sciousness, is  to  have  present  its  image,  which  is  the  same 
sensation  revived.  The  other  way,  on  the  contrary,  that  is 
external  perception,  is  indirect ;  it  teaches  us  nothing  as  to 
the  special  characters  of  its  object ;  it  simply  informs  us  of  a 
certain  class  of  its  effects.  The  object  is  not  directly  mani- 
fested to  us  it  is  denoted  indirectly  by  the  group  of  sensations 


1 86  OF  MENTAL  EVENTS.  [BOOK  IV. 

it  arouses,  or  would  arouse  in  us.*  In  itself,  excepting  as  to 
character  we  shall  examine  later  on,  this  physical  and  sensible 
object  remains  wholly  unknown  to  us ;  all  we  know  respecting 
it,  is  the  group  of  sensations  it  excites  in  us.  All  we  know  of 
the  cerebral  molecules,  are  the  sensations  of  grayish  color,  of 
flabby  consistance,  of  form,  volume,  and  other  analogous  ones, 
which  these  molecules  excite  in  us,  directly  or  through  the 
microscope,  in  a  crude  state  or  after  preparation  that  is  to 
say,  their  constant  effects  upon  us,  the  fixed  accompaniments, 
their  signs,  nothing  but  their  signs,  signs  and  indications  of 
unknown  things. — There  is,  then,  a  great  difference  between 
the  two  aspects.  By  consciousness,  I  attain  the  fact  itself; 
by  the  senses,  I  attain  a  sign  only.  A  sign  of  what  ?  What 
is  it  that  is  constantly  accompanied,  denoted,  signified  by  the 
internal  movement  of  the  nervous  centres  ?  We  have  shewn 
this  previously  when  explaining  the  conditions  of  sensations 
and  images  ;  it  is  the  sensation,  the  image,  the  internal  men- 
tal event.  All  is  then.in  accordance.  This  mental  event,  which 
consciousness  attains  directly,  can  only  be  attained  indirectly 
by  the  senses  ;  the  senses  know  nothing  of  it  but  its  effect  on 
them;  that  is  why  they  cause  us  to  conceive  it  as  a  cerebral 
movement  of  gray  cells  ;  as  it  acts  on  them  from  without  only, 
it  cannot  appear  to  them  otherwise  than  as  external  and 
physical. — Here  is  a  direct  and  remarkable  confirmation  of 
the  admitted  hypothesis,  and  we  now  understand  how  it  is 
the  mental  event  being  single,  necessarily  appears  double ; 
the  sign  and  the  event  signified  are  two  things  which  can  no 
more  be  confounded  than  separated,  and  their  distinction  is 
as  necessary  as  their  connection.  But,  in  this  connection  and 
in  this  distinction,  all  the  advantage  is  on  the  side  of  the 
mental  event ;  it  alone  exists ;  the  physical  event  is  but  the 
way  in  which  it  affects  or  is  capable  of  affecting  our  senses. 
The  physical  world,  then  is  reduced  to  a  system  of  signs,  and 
all  that  remains  to  enable  us  to  construct  and  conceive  it  are 
the  materials  of  the  moral  world. 


*  See  post  Part  ii.  book  5i.  chaps,  i  and  2.  See  too,  the  admirable  chapters  on 
the  Theory  of  the  Belief  in  an  External  World  and  on  the  Primary  Qualities  of 
of  Matter,  in  Mill's  "  Examination  of  Sir  W.  Hamilton's  Philosophy.  " 


CHAP.  II.]    THE  NERVOUS  CENTRES  AND  THOUGHTS.  jg/ 

What  are  these  materials  ?  We  have  seen  that  the  sen- 
sation, strictly  so  called,  is  a  compound  of  successive  and  simul- 
taneous events  of  the  same  quality,  themselves  composed  in 
the  same  way ;  that  at  the  extremity  of  our  analysis,  indirect 
experience  and  analogies  still  show  successive  and  simultaneous 
events  of  the  same  quality,  all  remote  from  consciousness 
and  becoming  at  last  infinitesimal ;  that  reflex  actions  indicate 
analogous  rudimentary  events,  and  that  these  may  be  traced 
even  at  the  lowest  point  of  the  animal  scale,  even  in  animals 
like  the  fresh-water  polypus  in  which  no  trace  of  a  nervous 
system  has  been  found.* — But  they  may  be  traced  still  further 
than  this  ;  for,  in  many  plants  like  the  sensitive  plant  and  the 
oscillating  clover  of  Bengal,  in  the  antherozoides,  of  cryp- 
togamia  and  the  zoospores  of  the  algae,  reflex  actions  are 
met  with  wholly  similar  to  those  produced  by  the  trunk  of  a 
decapitated  frog.  "  There  is  no  radical  difference  between 
animals  and  vegetables,"  when  looked  at  in  this  light. — No 
more  again  is  there  when  looked  at  in  the  light  of  internal 
structure,  or  of  chemical  composition.  The  two  kingdoms 
are  so  confounded  together  in  their  lower  branches,  that  many 
groups,  among  others  the  Vibriae,  have  sometimes  been  class- 
ified in  the  one,  sometimes  in  the  other.  In  fact,  "  the  nervous 
system  is  but  a  perfectioned  apparatus,"  and  the  mental  event 
of  which  it  is  the  condition,  and  of  which  its  action  is  the  sign 
is  a  complex  and  organized  group  whose  elements  and  rudi- 
ments may  also  be  met  with  elsewhere. — By  pursuing  analogies 
then,  we  may  descend  still  lower  in  the  scale  of  beings.  Be- 
neath the  organic  world  extends  tbe  inorganic,  and  the  first 
is  but  a  case  of  the  second.  It  is  constructed  with  the  same 
chemical  substances,  subject  to  the  same  physical  forces,  gov- 
erned by  the  same  mechanical  laws,  and  all  the  indications  of 
science  concur  in  representing  it  as  differing  in  degree  but 
identical  in  nature  ;f  what  we  term  life  is  a  more  delicate 
chemical  action  of  more  complex  chemical  elements.  In 
pursuing  our  analysis,  from  the  highest  operations  of  the 


*  Vulpian,  43,  3?,  31. 

\  Bertholet,    "  Chimie   Organique.  "   ii.  conclusion    Berard.  "  Elements    de 
Physiologic,"  ii.  65.  Saigey,  "  De  1'Unite  des  Phenomenes  Physiques,"  passim. 


1 88  OF  MENTAL  EVENTS.  [BOOK  IV. 

cerebral  lobes  to  the  most  elementary  phenomena  of  physics, 
we  find  nothing  but  mechanical  movements  of  atoms,  trans- 
missible without  loss  from  one  system  to  another,  and  so  much 
the  more  complicated  as  the  systems  become  more  complex. 
By  correspondence,  the  same  degradation  and  the  same  redac- 
tion occur  in  mental  events ;  at  the  highest  degree  of  compli- 
cation, they  constitute  images,  sensations,  strictly  so  called, 
and  those  rudimentary  sensations  which  reflex  action  denotes  ; 
in  the  next  degrees,  they  are  still  events  of  the  same  kind,  but 
less  compound,  and  so  on,  their  complication  diminishing 
with  that  of  the  molecular  movement,  till  at  last,  to  the  most 
simple  degree  of  the  physical  event,  corresponds  the  most 
simple  degree  of  the  mental  event. 

V.  Nature,  then,  has  two  faces,  and  the  successive  and 
simultaneous  events  of  which  she  is  made  up  may  be  conceived 
and  known  in  two  ways,  internally  and  in  themselves,  exter- 
nally and  by  the  impression  they  make  on  our  senses.     The 
two  faces  are  parallel,  and  every  line  cutting  the  one  cuts  the 
other  at  the  same  level.     When  seen  from  the  one  side,  na- 
ture has,  as  elements,  events  of  which  we  can  know  nothing 
except  when  in  a  state  of  extreme  complication,  and  which,  in 
this  state,  we  term  sensations.     Seen  from  the  other  side,  she 
has,  as  elements,  events  which  we  can  only  conceive  clearly 
when  in  a  state  of  extreme  simplicity,  and  which,  in  this  state, 
we  term  molecular  movements.     From  the  first  point,  she  is 
a  scale  of  successive  and  simultaneous  mental  events,' whose 
complication  goes  on  decreasing,  if  we  start  from  the  summit 
of  which  we  are  conscious,  to  descend  to  the  base  of  which 
we  are  unconscious.     From  the  second  point,  she  is  a  scale 
of  successive  and  simultaneous  physical  events,  whose  compli- 
cation goes  on  increasing,  if  we  start  from  the  base  which  we 
clearly  conceive,  to  ascend  to  the  summit  of  which  we  have 
no  precise  idea.     Every  degree  of  complication  on  one  side 
of  the  scale  indicates  an  equal  degree  of  complication  on  the 
other.     On  both  sides,  at  the  base  of  the  scale  the  events  are 
infinitesimal ;  we  have  seen  in  the  case  of  those  sensations 
which  we  have  been  able  to  a  certain  extent  to  analyze,  those 
of  hearing  and  sight,  that  the  mental  event,  as  the  physical 
event,  passes  in  a  very  short  time  through  a  strictly  infinite 


CHAP.  II.]  THE  NERVOUS  CENTRES  AND   THOUGHTS. 

series  of  degrees.  From  base  to  summit,  the  correspondence 
on  either  side  is  perfect.  Phrase  for  phrase,  word  for  word, 
the  physical  event,  as  we  represent  it  to  ourselves,  translates 
the  mental  event. 

Let  the  reader  follow  out  the  comparison  to  the  end  ;  it 
will  express  the  matter  with  all  its  details.  Suppose  a  book 
written  in  an  original  tongue  and  furnished  with  an  interlinear 
translation  ;  the  book  is  nature,  the  original  language  is  the 
mental  event,  the  interlinear  translation  is  the  physical  event, 
and  the  order  of  the  chapters  is  the  order  of  beings. — At  the 
beginning  of  the  book,  the  translations  is  printed  in  clear  and 
legible  characters.  But  these  become  less  so,  as  we  go  on, 
and  here  and  there,  from  chapter  to  chapter,  new  characters 
creep  in,  which  we  have  difficulty  in  connecting  with  the 
earlier  ones.  At  last,  and  above  all  in  the  final  chapter,  the 
impression  can  no  longer  be  deciphered  ;  but  we  have  abun- 
dance of  evidence  that  it  is  still  the  same  book  and  the  same 
language. — It  is  just  the  reverse  with  the  original  text.  It  is 
very  legible  at  the  last  chapter  ;  in  the  one  before  it  the  ink 
is  pale  ;  in  earlier  chapters  we  can  still  discover  that  there  is 
printing,  but  can  read  nothing  of  it ;  before  that  again,  all 
trace  of  ink  has  disappeared. 

Such  is  the  book  philosophers  attempt  to  understand ; 
before  the  final  unintelligibility  of  the  first  writing,  and  before 
the  enormous  gaps  of  the  second,  they  stop  embarrassed 
and  each  one  decides,  not  from  the  facts  in  evidence  but 
from  the  habits  of  his  mind  and  the  wants  of  his  heart. — • 
Scientific  men  properly  so  called,  physicists  and  physiologists 
who  have  begun  the  book  at  the  beginning,  say  that  it  con- 
tains but  one  language,  that  of  the  interlinear  translation, 
and  that  the  other  is  reducible  to  it ;  an  enormous  supposi- 
tion, since  the  two  languages  are  wholly  different. — Moralists, 
psychologists,  and  religious  minds  who  have  commenced  the 
book  at  the  end,  and  are  nevertheless  forced  to  confess  that 
the  bulk  of  the  work  is  written  in  another  idiom,  find  an  in- 
explicable mystery  in  this  assemblage  of  two  languages,  and 
usually  declare  that  there  are  two  books  put  in  juxtaposition 
and  beside  one  another.  In  short,  materialists  disallow  the 
text,  and  spiritualists  declare  the  connection  of  text  and 


I  OX)  OF  MENTAL  EVENTS.  [BOOK  IV. 

translation  to  be  inexplicable. — We  have  not  proceeded 
in  this  way,  and  our  minute  analysis  has  led  us  to  a  new 
solution.  We  have  first  studied  for  a  long  time  the  orig- 
inal idiom,  and  have  shown  that  the  pages  of  the  last  chap- 
ter, which  appear  to  be  written  in  various  kinds  of  characters, 
are  all  written  in  the  same  character.  Profiting  by  this  re- 
duction, we  have  then  deciphered  many  half-obliterated  lines 
of  the  chapter  preceeding  it ;  then,  from  the  vague  traces 
left  on  the  earlier  pages,  we  have  conjectured  that  the  text 
is  continued  much  further  back,  even  on  those  pages  on 
which  no  trace  of  it  is  visible.  We  then  prove  the  interlinear 
writing  to  be  a  translation,  and  the  other  to  be  an  original 
text ;  and  have  concluded,  from  their  dependence,  that  the 
first  is  the  translation  of  the  second.  On  this  evidence  we 
have  admitted  that  the  text,  though  invisible  to  our  eyes, 
must  be  continued  on  the  earlier  pages,  and  that,  on  the  final 
pages,  the  interlinear  writing,  though  it  cannot  be  deciphered 
is  still  a  translation.  In  this  way,  the  unity  of  the  book  has 
been  proved,  and  the  two  idioms  are  completed  or  explained 
by  one  another.  We  now  know  which  of  them  is  the  origin- 
al testimony  and  deserves  our  confidence,  and  to  what  ex- 
tent and  with  what  assurance  we  may  consult  the  other. 
Thanks  to  their  mutual  dependence  and  to  the  continual 
presence  of  one  or  other  of  them,  each  of  them  may  supply 
the  place  of  the  other.  When  one  of  them  is  effaced  or  in- 
capable of  being  deciphered,  we  are  entitled  to  draw  conclu- 
sions, from  the  one  we  can  read,  to  the  other  which  has  be- 
come unreadable.* 


*  To  complete  this  theory,  seefost,  note  at  the  end  of  sect,  vii,  ihap.  i,book 
ii.  part  ii. 


CuAP.  III.]  SELF  AND    THE   ORGANIZED  BODY. 


CHAPTER  III. 

THE  HUMAN  PERSON  AND  THE  PHYSIOLOGICAL  INDIVIDUAL. 

I.  HITHERTO  we  have  considered  our  events,  without  oc- 
cupying ourselves  with  the  being  they  appertain  to,  and  which 
each  of  us  calls  himself.  We  must  now  examine  this  being. 
Philosophers  usually  give,  it  the  principle  place,  and  a  place, 
wholly  distinct.  "  I  experience  sensation,  say  they,  I  have 
recollections,  I  combine  images  and  ideas,  I  perceive  and 
conceive  external  objects.  This  Ego  or  self,  unique,  per- 
sistent, and  always  the  same,  is  something  different  from 
my  sensations,  recollections,  images,  ideas,  perceptions,  and 
conceptions,  which  are  various  and  transient.  Besides  this, 
it  is  capable  of  experiencing  some  of  these  and  of  produc- 
ing the  rest ;  and  thus  it  possesses  powers  or  faculties. 
Now  these  faculties  reside  in  it  in  a  stable  manner ;  by  them 
it  feels,  recollects,  perceives,  conceives,  combines  images  and 
ideas  ;  it  is,  then,  an  efficient  and  productive  cause." — Thus 
they  arrive  at  considering  the  Ego  as  a  subject  or  substance, 
having  for  its  distinctive  qualities  certain  faculties,  and  they 
suppose  that,  beneath  our  mental  events,  there  are  two  kinds 
of  explicative  entities,  first  the  powers  or  faculties  experienc- 
ing or  producing  them,  then  the  subject,  substance,  or  soul 
possessing  these  faculties.* 

Now  these  are  metaphysical  entities,  pure  phantoms,  be- 
gotten of  words,  and  vanishing  as  soon  as  we  examine  rigor- 
ously the  meanings  of  the  words.  What  is  a  power  ? — A  des- 
potic sovereign  has  absolute  power  ;  this  means  that,  as  soon 
as  he  commands  a  thing  to  be  done,  whatever  it  may  be,  the 
confiscation  of  property,  the  death  of  a  man,  it  will  be  done. 
— A  constitutional  king  has  limited  power  only ;  this  means 


*  Gamier,  "  Traite  des  facultes  de  Tame,"  vol.  i.  books  i.  and  ii.    See  Jouffiroy 
and  Maine  de  Biran  for  the  theory  of  these  scholastic  entities. 


I02  OF  MENTAL  EVENTS.  [BOOK  IV. 

that  if  he  commands  certain  things,  the  dismissal  of  a  minis- 
ter, the  promulgation  of  a  law,  they  will  be  done ;  but  that, 
if  he  orders  other  things,  such  things,  for  instance,  as  we  men- 
tioned just  now,  they  will  not  be  done;  this  is  all  that  is 
meant.  All  that  the  word  power  here  denotes  is  a  constant 
connection  between  one  fact,  the  order  of  a  prince,  and  cer- 
tain other  facts  following  it. — And  so  again  we  say  that  a 
healthy  man  has  power  to  walk  and  a  paralytic  man  has  not ; 
this  simply  means  to  say  that,  in  the  healthy  man,  the  resolu- 
tion to  walk  is  certainly  followed  by  the  movement  of  his  legs, 
and  this  resolution  is  never  so  followed  in  the  case  of  the  par- 
alytic ;  here  again  power  is  but  the  perpetual  connection  be- 
tween one  fact  which  is  antecedent  and  another  which  is 
consequent. 

So  again  with  force.  A  particular  horse  has  force  enough 
to  draw  a  cart  weighing  five  thousand  kilogrammes,  and  has 
not  force  enough  to  draw  the  same  cart  when  more  heavily 
loaded.  A  particular  stream  of  water  has  force  enough  to 
move  a  wheel,  and  has  not  force  enough  to  move  a  heavier 
wheel.  This  means  that,  when  the  horse's  muscles  are  con- 
tracted, the  cart  of  five  thousand  kilogrammes  will  be  moved, 
and  the  other  cart  will  not  be  moved :  that  when  the  stream 
falls  on  the  boards  of  the  wheels,  the  first  one  will  turn  and 
the  second  one  will  not.  Here  we  have  connections  only, 
one  between  the  muscular  contractions  of  the  horse  and  the 
movement  of  the  cart ;  the  other  between  the  stream  of  water 
and  the  wheel  turning  round.  A  particular  force  exists  when 
a  particular  connection  exists ;  it  ceases  when  this  connection 
ceases.  When  two  events  are  connected,  and  the  second  of 
them  has  a  particular  magnitude  when  compared  to  others 
similar  to  it,  we  say  that  the  force  has  a  particular  magnitude. 
When  the  magnitude  of  the  second  event  is  double,  the  mag- 
nitude of  the  force  is  double.  The  force  of  the  muscular  con- 
traction is  double,  if  the  cart  moved  weighs  ten  thousand 
kilogrammes  instead  of  five  thousand  ;  the  force  of  the  stream 
of  water  is  double,  if  the  wheel  set  turning  is  twice  as  heavy 
as  the  first  wheel.  In  general,  if  we  are  given  two  facts, 
one  antecedent  and  the  other  consequent,  connected  by  a 
constant  link,  we  term  the  particularity  of  the  antecedent  to 


CHAP.  III.]         SELF  AND    THE   ORGANIZED  BODY.  JQ-I 

be  always  followed  by  the  consequent,  force,  and  we  measure 
this  force  by  the  magnitude  of  the  consequent. 

The  names  power  and  force,  then,  do  not  denote  any  mys- 
terious being,  any  occult  essence.  When  I  say  that  I  have 
power  or  force  to  move  my  arm,  I  merely  wish  to  say  that 
my  resolution  to  move  my  arm  is  constantly  followed  by  the 
movement  of  my  arm.  In  fact,  if,  with  the  aid  of  physiology, 
I  examine  this  operation  somewhat  more  closely,  I  find  in  it 
a  number  of  intermediate  steps — a  molecular  movement  in 
cerebral  lobes,  another  molecular  movement  in  the  cerebellum, 
another  molecular  movement  propagated  along  the  marrow, 
and  thence  into  the  motor  nerves  of  the  arm,  a  contraction 
of  the  muscles  of  the  arm,  a  displacement  of  their  points  of 
attachment.  I  have  power  to  move  my  arm  in  the  same  sense 
that  a  person  working  the  telegraph  at  Marseilles  has  power 
to  move  the  telegraph  needles  at  Paris.  Between  my  resolu- 
tion and  the  displacement  of  my  arm,  there  are  all  the  inter- 
mediate steps  enumerated  ;  between  the  operator  at  Marseilles 
and  the  needles  at  Paris,  there  are  a  thousand  kilometres  of 
telegraph  wire.  It  is  a  constant  particularity  that  the  signals 
of  the  worker  are  followed  a  thousand  kilometres  off  by  the 
play  of  the  indicating  needles ;  it  is  a  constant  particularity 
that  my  resolution  is  followed,  through  ten  indispensable  in- 
termediate links,  by  the  movement  of  my  arm.  There  is 
nothing  more  than  this. — Unfortunately,  of  this  particularity, 
which  is  a  relation,  we  construct,  by  a  mental  fiction,  a  sub- 
stance ;  we  describe  it  by  a  substantive  name,  force  or  power ; 
we  attribute  qualites  to  it ;  we  say  that  it  is  greater  or  less ; 
we  employ  it  in  language  as  a  subject ;  we  forget  that  its  ex- 
istence is  wholly  verbal,  that  it  derives  it  from  ourselves,  that 
it  has  received  it  by  way  of  loan,  provisionally,  for  conveni- 
ence of  discourse,  and  that,  being  simply  a  relation,  it  is  noth- 
ing in  itself.  Led  away  by  language  and  custom,  we  suppose 
there  is  something  real  in  it,  and  reasoning  from  false  premis- 
es, increase  our  error  at  every  step. — In  the  first  place,  as  the 
being  in  question  is  a  pure  nonentity,  we  can  find  nothing  in 
it  but  emptiness  ;  this  is  why,  by  an  illusion  of  which  we  have 
already  seen  instances,*  we  make  of  it  a  pure  essence,  unex- 


13  *  See  ante,  book  i.  chap.  3,  p.  33. 


104  OF  MENTAL  EVENTS.  [BOOK  IV. 

tended,  incorporeal,  in  short,  spiritual.* — In  the  second  place, 
as  the  event  only  arises  through  this  force,  the  event  is  want- 
ing if  the  force  is  wanting  ;  the  force  is  the  cause  of  the  event. 
Besides  this,  it  precedes  and  survives  the  event ;  it  is  per- 
manent while  the  event  is  transient ;  the  event  may  be  repeat- 
ed or  changed,  the  force  is  always  one  and  the  same ;  it  may 
be  compared  to  an  inexhaustible  stream,  of  which  the  event 
is  a  wave.  Hence  we  come  to  consider  it  as  an  essence  of  a 
higher  order,  placed  above  the  facts,  stable,  monadic,  creative. 
From  its  model,  philosophers  go  on  to  people  the  universe 
with  similar  entities.  And  yet,  it  is  in  itself  nothing  more 
than  a  character,  a  property,  a  particularity  of  a  fact,  the  par- 
ticularity of  being  always  followed  by  another  fact,  a  particu- 
larity detached  from  the  fact  by  abstraction,  set  apart  by  fiction, 
kept  in  a  distinct  state  by  means  of  a  distinct  substantive 
name,  till  the  mind,  forgetting  its  origin,  believes  it  to  be  in- 
dependent, and  becomes  the  dupe  of  an  illusion  of  its  own  ef- 
fecting. 

II.    The  fall  of  this  illusion  causes  the  fall  of  another. 
"  Power,"  say  the  spiritualists,  "  identifies  itself  with  the  being 

possessing  it That  something  by  which  we  can  ought 

not  to  be  considered  as  distinct  from  the  soul."f  The  facul- 
ties and  forces  of  the  Ego,  then,  are  Ego  itself,  or  at  least  a 
portion  of  the  Ego ;  many  spiritualists  go  so  far  as  to  admit, 
with  Leibnitz,  that  the  Ego,  is  nothing  more  than  a  force, 
and  that  in  general  the  notions  of  force  and  substance  are 
equivalent.  Now  we  have  just  seen  that  powers  and  forces 
are  but  verbal  entities  and  metaphysical  phantoms.  So  far, 
therefore,  as  it  is  made  up  of  forces  and  powers,  the  Ego  it- 
self ?s  but  a  verbal  entity  and  a  metaphysical  phantom.  That 
inner  something  of  which  the  faculties  were  different  aspects, 
disappeared  with  them ;  the  one  permanent  substance,  dis- 


*  "  Causes  are  not  material  ;  their  activities  are  necessarily  immaterial.  Forces 
seize  on  matter,  conform  it  to  themselves  and  manifest  themselves  by  their  effects 
on  its  surface,  they  are  signified  and  interpreted  by  the  qualities  they  impose  on 

matter The  real  cause  which  sets  in  motion  the  heart,  the  stomach,  and 

other  organs,  is  external  and  superior  to  those  organs." — Jouffroy,  "  Esthetique," 
132,  145  ;  "  Nonveaux  Melanges,"  233  to  273. 

f  Gamier,"  Traite  des  faculties  de  Tame,"  i.  44. 


CHAP.  III.]          SELF  AND    THE   ORGANIZED  BODY.  ^ 

tinct  from  events,  is  seen  to  vanish  and  re-enter  the  region 
of  words.  All  that  remains  of  us  are  our  events,  sensations, 
images,  recollections,  ideas,  resolutions :  these  are  what  con- 
stitute our  being ;  and  the  analysis  of  our  most  elementary 
judgments  shows,  in  fact,  that  our  Self  has  no  other  ele- 
ments. 

Take  a  sensation  of  taste,  then  a  pain  in  the  leg,  then  the 
recollection  of  a  concert.  I  taste,  I  suffer,  I  recollect.  In  all 
these  words  we  find  the  verb  to  be,  and  all  these  judgments 
contain  the  subject  /  connected  by  the  verb  to  be,  with  a  par- 
ticiple denoting  an  attribute.  Now,  in  every  judgment,  the 
verb  is  expresses  that  the  attribute  is  an  element,  a  fragment, 
an  extract  of  the  subject,  included  in  it,  as  a  portion  in  a 
whole;  this  is  the  whole  sense  and  office  of  the  verb  to  be; 
and  it  is  the  same  with  it  here  as  in  other  cases.  Here,  then, 
the  verb  expresses  that  the  sensation  of  taste,  the  pain,  the 
recollection  of  the  concert,  are  elements,  fragments,  extracts, 
of  the  Ego.  Our  successive  events  then  are  successive  com- 
ponents of  ourselves.  The  Ego  is  in  turn  each  of  these 
events.  At  one  moment,  as  was  clearly  seen  by  Condillac,  it 
is  nothing  more  than  the  sensation  of  taste,  at  the  second, 
moment,  nothing  more  than  suffering,  at  the  third,  nothing 
more  than  the  recollection  of  the  concert. — Not  that  it  is  a 
simple  whole  ;  for  the  verb  is,  which  connects  the  subject  to 
the  attribute,  expresses,  not  only  that  the  attribute  is  included 
in  the  subject  as  a  portion  in  a  whole,  but  further,  that  the 
existence  of  the  whole  precedes  its  division.  Whatever  be 
the  origin  of  a  judgment,  the  attribute  is  always,  in  relation 
to  the  subject,  an  artificial  fragment  in  relation  to  a  natural 
whole.  The  mind  extracts  the  fragment,  but,  at  the  same 
moment,  recognizes  that  this  extraction  or  abstraction  is 
purely  fictitious,  and  that,  if  the  fragment  exists  apart,  it  is 
from  the  mind's  having  set  it  apart.  In  fact,  it  is  simply  for 
the  convenience  of  studying  them  that  we  separate  our  events 
from  one  another ;  they  actually  form  a  continuous  web  in 
which  our  inspection  sets  boundaries  by  arbitrary  severings.* 
The  operation  we  perform  resembles  that  of  a  man  who  the 


*  "  Les  Philosophes  Francais  du  xixme  Siecle,"  par  H.  Taine,  3rd  ed.  p.  250. 


jgg  OF  MENTAL  EVENTS.  fBoOK  IV. 

better  to  know  a  long  plank  divides  it  into  triangles,  rhom- 
boids, and  squares,  all  marked  out  with  chalk.  The  plank 
remains  one  and  continuous;  we  cannot  say  that  it  is  simply 
the  series  of  its  portions  placed  end  to  end,  since  it  is  only 
divided  to  the  eye  ;  but  still  it  is  equivalent  to  the  series  of 
these  portions  ;  if  they  were  taken  away,  nothing  would  re- 
main ;  they  constitute  it.  In  the  same  way  the  Ego  remains 
one  and  continuous ;  we  cannot  say  that  it  is  the  series  of  its 
events  placed  in  succession,  since  it  is  not  divided  into  events 
except  to  observation  ;  but  still  it  is  equivalent  to  the  series 
of  these  events ;  if  they  were  taken  away,  nothing  would  re- 
main ;  they  constitute  it.  When  we  separate  them  from  it, 
we  do  as  a  man  would  who  should  say,  after  going  over  the 
several  divisions  of  the  plank,  "  This  plank  is  a  square  here, 
just  now  it  was  a  rhomboid,  presently  it  will  be  a  triangle; 
through  all  my  advancing,  retreating,  recalling  the  past,  foresee- 
ing the  future,  I  always  find  an  invariable,  identical  single 
plank,  though  its  divisions  vary ;  it  then  is  different  from  them, 
it  is  a  distinct  subsisting  being,  that  is  to  say,  an  independent 
substance  of  which  the  rhomboids,  triangles,  and  squares  are 
but  successive  states."  By  an  optical  illusion,  such  a  man 
would  create  an  empty  substance — the  plank  in  itself.  By  a 
similar  illusion,  we  create  an  empty  substance — the  Ego  in 
itself. — Just  as  the  plank  is  nothing  more  than  the  continuous 
series  of  its  successive  divisions,  so,  the  Ego  is  nothing  more 
than  the  continuous  web  of  its  successive  events.  If  we  con- 
sider it  at  a  given  moment,  it  is  nothing  more  than  a  portion 
severed  from  the  web,  that  is  to  say,  a  group  of  simultaneous 
events,  about  to  be  made  up  and  then  undone,  some  salient 
sensation  among  other  less  salient  ones,  some  preponderant 
image  among  others  about  to  fade  away.  At  any  other  mo- 
ment, the  portion  severed  is  analogous ;  it  is  no  other  and  no 
more  than  this. 

If  now  we  classify  these  various  events,  sensations, 
images,  ideas,  resolutions;  if  we  impose  a  name  on  each 
class,  sensibility,  imagination,  understanding,  will ;  if  we  at- 
tribute to  the  Ego  various  powers,  that  of  feeling,  that  of 
imagining,  that  of  willing ;  this  is  permissible  and  useful. 
But  we  must  never  forget  what  underlies  these  words ;  we 


CHAP.  III.]          SELF  AND    THE   ORGANIZED  BODY.  ^7 

mean  simply  to  say  that  this  being  feels,  imagines,  thinks, 
wills,  and  that,  if  things  remain  the  same,  it  will  feel,  imagine, 
think,  and  will.  When  we  outstep  this  vague  proposition, 
we  mean  to  say  that,  certain  conditions  being  given,  this  be- 
ing will  have  a  certain  sensation,  image,  idea,  or  resolution, 
in  other  words,  that  in  the  web  constituting  it  there  is  a  con- 
stant connection  with  some  event  internal  or  external. — I 
have  the  power  of  recalling  a  picture,  the  Marriage  at  Cana 
by  Veronese ;  this  means  that  my  present  time  of  life,  and 
with  my  present  memory,  the  resolution  to  recall  the  picture 
is  constantly  followed,  after  the  lapse  of  a  certain  time,  by 
the  internal  revival,  more  or  less  clear  and  complete,  of  the 
figures  and  architecture  of  which  the  picture  is  composed. — I 
have  the  faculty  of  perceiving  an  external  object,  this  table, 
for  instance ;  this  means  that  in  my  present  state  of  health, 
without  amaurosis,  or  tactile  muscular  paralysis,  if  the  table 
be  in  the  light,  if  it  be  within  the  range  of  my  hand  and  my 
eyes,  if  I  turn  my  eyes  towards  it,  or  stretch  out  my  hand 
upon  it,  these  two  actions  will  be  constantly  followed  by  the 
perception  of  the  table. — The  forces,  faculties,  or  powers 
appertaining  to  this  web  are  nothing  more,  then,  than  the 
property  which  any  particular  event  of  the  web  has  of  being 
constantly  followed,  under  various  conditions,  external  or  in- 
ternal, by  some  particular  internal  or  external  event.  There 
is  nothing  in  the  web,  then,  but  its  events,  and  the  more  or 
less  distant  connections  which  they  have  with  one  another  or 
with  external  events ;  and  the  Ego,  that  is  the  web,  contains 
nothing  beyond  its  events  and  their  connections. 

The  destruction  of  this  metaphysical  phantom  lays  low 
one  of  the  principle  survivors  of  that  army  of  verbal  entities 
which  formerly  invaded  all  the  provinces  of  nature,  and 
which  during  the  last  three  hundred  years,  the  progress  of 
the  sciences  has  one  by  one  upset.  There  are  two  only  left 
at  present,  the  Ego  and  matter ;  but  at  that  time,  during  the 
avowed  or  dissembled  empire  of  the  scholastic  philosophy, 
men  imagined  that,  underlying  events,  were  a  number  of 
chimerical  beings — the  vital  principle,  the  vegetable  soul,  sub- 
stantial forms,  occult  qualities,  plastic  forces,  specific  virtues, 
affinities,  appetites,  energies,  archaea,  in  short,  a  population 


198 


OF  MENTAL  EVENTS. 


of  mysterious  agents,  distinct  from  matter,  connected  with 
matter,  and  believed  to  be  indispensable  to  explain  its  trans- 
formations.     They  have  gradually  vanished  at  the  contact 
of  experience.     Nowadays,  when   scientific   men   speak   of 
forces,  physiological,  chemical,  physical,  or  mechanical,  they 
see   that   these   names   are  names   only.     Their  efforts  are 
limited  to  the  proof  of  constant  connections ;  when  they  ex- 
plain a  fact,  it  is  by  means  of  another  fact.     At  the  highest 
point  of  their  theories*  they  establish  couples  of  very  gen- 
eral events,  the  first  antecedents,  the  second  consequents,  the 
second   following  the  first  without  exception  or  condition  ; 
from  these  couples  they  deduce  other  things.     If  they  use 
the  word  force  it  is  to  denote  the  constant  connection  between 
the  second  and  the  first.     If  they  admit  different  forces,  it  is 
because,  in  the  present  state  of  our  knowledge,  the  couples 
to  which  certain  groups  of  events   are  reduced  cannot   be 
reduced  to  one  another  or  to  other  couples.     In  short,  verbal 
entities  no  longer  subsist  except  at  the  two  extremities  of 
science — in  psychology,  by  the  notion  of  self  and  its  faculties  ; 
in  the  preliminary  parts  of  physics  by  the  notion  of  matter 
and  of  its  primitive  forces. — Hitherto,  and  in  France  especi- 
ally, this  illusion  has  obstructed  psychology ;  men  have  ap- 
plied themselves  to  observing  the  pure  Ego  ;  they  have  at- 
tempted to  see  in  the  faculties  "  the  causes  which  produce 
the  phenomena  of  the  soul ;  "f  they  have  studied  the  reason 
— the  faculty  which  produces  ideas  of  the  infinite,  and  dis- 
covers  necessary  truths  ;    the  will — the  faculty  which   pro- 
duces free  resolutions.     They  have  thus  constructed  a  science 
of  words  alone.     "  From  a  pictured  hook,"  says  an  English 
philosopher,  "  we  can  hang  only  a  pictured  chain."     Let  us 
lay  aside  words,  let  us  study  events,  which  alone   are   real, 
their  conditions,  their  dependencies,  and  it  is  certain,  that  by 
following  the  path  struck  out  by  Condillac,  and  cleared  by 
James  Mill  and  his  English  successors,  we    shall   gradually 
arrive  at  the  construction  of  a  science  of  things  and  of  facts. 
III.  Having  upset  this  entity  at  the  summit  of  nature, 


*  See  Mill's  "  Logic,"  and  especially  the  theory  of  Induction, 
f  Gamier,  "  Traite  des  Facultes  de  1'Ame,"  i.  33. 


CHAP.  III.]         SELF  AND    THE   ORGANIZED  BODY.  IQQ 

there  remains,  at  the  foot  of  nature,  another  entity,  matter, 
which  falls  by  the  same  blow.  Hitherto,  the  most  faithful 
followers  of  experience  have  admitted,  at  the  foundation  of 
all  corporeal  events,  a  primitive  substance,  matter  possessed 
of  force.  Positivists  themselves  underwent  this  illusion  ;  in 
spite  of  their  reducing  all  knowledge  to  the  discovery  of  facts 
and  their  laws.  Beyond  the  accessible  region  of  facts  and 
laws,  they  placed  an  inaccessible  region,  that  of  substances, 
real  things,  the  knowledge  of  which  would  certainly  be  most 
precious,  but  in  whose  direction  research  ought  not  to  stray, 
since  experience  attests  the  futility  of  all  inquiry  respecting 
them.  Now  the  analysis  which  reduces  substance  and  force 
to  verbal  entities  is  applicable  to  matter  as  well  as  to  mind. 
In  the  physical  as  in  the  moral  world,  force  is  that  particulari- 
ty which  a  fact  has  of  being  constantly  followed  by  another 
fact.  Isolated  by  abstraction,  and  denoted  by  a  substantive 
name,  it  becomes  a  permanent  subsisting  being,  that  is  to  say, 
a  substance.  But  it  becomes  so  for  the  convenience  of  dis- 
course only,  and  the  attempt  to  make  anything  more  of  it,  is 
founded  on  a  metaphysical  illusion  like  that  which  sets  apart 
the  Ego  and  its  faculties.  Scientific  men  themselves  come 
involuntarily  to  this  conclusion  when,  provided  with  mathe- 
matical formulse  and  with  the  whole  of  the  facts  of  physics, 
they  attempt  to  conceive  the  ultimate  particles  of  matter.* 
For  they  arrive  at  picturing  atoms,  not  according  to  the  coarse 
imagination  of  the  crowd,  as  little  solid  masses,  but  as  pure 
geometric  centres,  with  relation  to  which,  first,  attractions, 
then  repulsions  increase  with  increasing  proximity.  In  all 
this  there  are  but  movements,  present,  future,  or  possible, 
connected  with  certain  conditions,  variable  in  magnitude  and 
direction  according  to  a  certain  law,  and  determined  with  re- 
lation to  certain  points. 

Thus,  in  the  physical  as  in  the  moral  world,  nothing  re- 
mains of  what  is  commonly  understood  by  substance  and 
force ;  all  left  subsisting  are  events,  their  conditions  and  de- 
pendences, some  of  them  moral  or  conceived  on  the  type  of 


*  Renouvier,  "  Essais  de  Critique  Generale,"  2me  essai,  25  Exposition  of  the 
Ideas  of  Boscovich,  Ampere,  Poisson,  and  Cauchy. 


200  OF  MENTAL  EVENTS.  [BOOK  IV. 

sensation,  others  physical  or  conceived  on  the  type  of  motion. 
The  notion  of  fact  or  event  alone  corresponds  to  real  things. 
In  this  way,  the  Ego  is  a  being  as  much  as  the  chemical  body 
or  material  atom  ;  only  it  is  a  more  compound  being,  and  con- 
sequently subject  to  more  numerous  conditions  of  origin 
and  conservation.  Chemical  body,  material  atom,  self — that 
which  we  term  a  being,  is  always  a  distinct  series  of  events ; 
what  constitutes  the  forces  of  a  being  is  the  property  of  certain 
events  of  its  series  to  be  constantly  followed  by  some  particu- 
lar event  of  its  own  or  of  another  series  ;  what  constitutes  the 
substance  of  a  being  is  the  permanence  of  this  and  other  ana- 
logous properties.  This  is  why,  if  we  cast  a  general  glance 
over  nature,  and  drive  out  of  our  minds  the  phantoms  we  have 
set  up  betwaen  her  and  our  thought,  we  perceive  in  the  world 
nothing  more  than  simultaneous  series  of  successive  events, 
each  event  being  the  condition  of  another  and  having  another 
as  its  condition. 

IV.  This  being  settled,  we  have  no  difficulty  in  compre- 
hending the  connection  between  the  human  personality  and 
the  physiological  individual.  For  it  is  now  no  longer  a  ques- 
tion of  knowing  how  an  unextended  substance,  termed  soul, 
can  dwell  in  an  extended  substance,  termed  body,  or  how  two 
beings  of  nature  so  different  can  hold  intercourse  with  one 
another;  these  scholastic  questions  fall  to  the  ground  with 
the  scholastic  entities  which  suggested  them.  All  we  have 
now  before  our  eyes  is  a  series  of  events  termed  self,  connect- 
ed with  other  events  forming  its  condition.  Henceforward, 
there  is  nothing  strange  in  the  dependences  we  have  proved. 
The  web  of  facts  which  makes  up  our  being  is  a  distinct  dis- 
trict m  the  aggregate  constituted  by  the  nervous  functions, 
this  aggregate  itself  being  a  distinct  province  in  the  entire  liv- 
ing animal.  As  we  have  shown,  this  web  may  be  considered 
under  two  aspects,  directly,  in  itself  and  by  consciousness,  or  in- 
directly, by  external  perception  and  from  the  impressions  it 
produces  on  the  senses. — Next  to  ideas,  images,  and  sensa- 
tions, events  of  a  very  compound  nature,  of  which  we  are 
conscious,  and  which  are  thus  distinguished  from  other  analo- 
gous events,  are  other  rudimentary  and  elementary  events  of 
the  same  1-ind,  of  which  we  are  not  conscious,  and  whose  ex- 


CHAP.  III.]         SELF  AND    THE   ORGANIZED  BODY.  2OI 

tences  is  denoted  by  the  reflex  action  :  such  is  the  first  aspect. 
— Next  to  the  very  compound  molecular  movements  which 
take  place  in  the  gray  substance  of  the  cerebral  lobes  and  of  the 
centres  termed  sensory,  and  other  analogous  but  less  compound 
molecular  movements  which  take  place  in  the  gray  substance 
of  the  marrow  and  the  ganglia  of  the  sympathetic  nerve  ;*  this 
is  the  second  aspect. — The  first  is  the  psyschological  aspect ; 
the  second  is  the  physiological  aspect. — According  to  the 
second,  there  are  in  the  animal  many  centres  of  nervous  ac- 
tion, the  ganglia  of  the  great  sympathetic  nerve,  the  different 
segments  of  the  marrow,  the  different  departments  .  of  the 
encephalon,  more  or  less  subordinate  or  predominant,  more 
or  less  simple  or  complex,  but  all  distinct,  mutually  excitable, 
and  possessed  of  the  same  fundimental  properties. — According 
to  the  first,  there  are  in  the  animal  many  groups  of  mental 
events,  ideas,  images,  sensations  strictly  so  called,  rudimen- 
tary and  elementary  sensations,  all  more  or  less  subordinate 
or  predominat,  more  or  less  simple  or  complex,  but  distinct, 
mutually  excitable,  and  more  or  less  analogous  to  sensation. 
—By  somewhat  straining  language,  we  might  consider  the 
marrow  as  a  string  of  rudimentary  encephala,  and  the  ganglia 
of  the  sympathetic  nerve  as  a  network  of  still  more  rudiment- 
ary encephala.f  Consequently,  we  should  see,  in  the  groups 
of  rudimentary  sensations  of  which  we  are  not  conscious, 
rudimentary  souls ;  and  just  as  the  nervous  apparatus  is  a 
system  of  organs  in  different  states  of  complication,  so  the 
psychological  individual  would  be  a  system  of  souls  in  differ- 
ent degrees  of  development. 

We  must  not  take  these  metaphors  for  more  than  they  are 
worth,  that  is  to  say,  for  phrases  translating  into  ordinary 
language  the  positive  facts  we  have  proved.  But,  as  we  des- 
cend the  animal  kingdom  we  constantly  find  them  becoming 
more  and  more  exact;  the  mutual  dependence  of  the  nervous 
centres  becomes  less  strict ;  each  centre  is  less  affected  by 
being  cut  off  from  the  rest ;  and  when  isolated,  performs  its 


*  Experiments  of  Claude  Bernard  on  the  reflex  power  of  the  submaxillary 
ganglion. 

f  See  Landry,  "  Des  Paralysies,"  47,  cited  ante,  p.  184. 


202  OF  MENTAL  EVENTS.  [BooK  IV. 

functions  less  incompletely  and  for  a  longer  time.  We  have 
seen  that,  in  a  triton  or  a  frog,  the  hindquarters  go  through 
complex  movements  when  separated  from  the  rest  of  the  body, 
movements  adapted  to  a  purpose,  and  capable,  under  altered 
circumstances,  of  adapting  themselves  to  another  purpose. 
These  co-odinated  movements  which  seem  to  denote  an  inten- 
tion, are  still  more  visible  in  the  severed  portions  of  insects.* 
This  extends  so  far  that  many  observers  have  seen  in  such 
movements  a  true  intention,  and  consequently  true  represen- 
tations, just  as  those  of  which  the  cerebral  lobes  are  the 
organs.  "  I  remove  rapidly  with  scissors,"  says  Duges,  "  the 
anterior  segment  of  the  thorax  of  the  Mantis  religiosa.  The 
posterior  part  of  the  body  still  remains  balanced  upon  the 
four  legs  which  belong  to  it,  resisting  and  attempt  to  over- 
throw it,  recovering  its  position  when  disturbed  and  perform- 
ing the  same  agitated  movements  of  the  wings  and  elytra,  as 
when  the  unmutilated  insect  is  irritated The  experi- 
ment may  be  pursued  in  a  more  striking  manner.  The  anter- 
ior part  of  the  thorax  contains  a  bilobed  ganglion,  sending 
out  nerves  to  the  arms  or  fore-limbs,  which  are  armed  with 
powerful  claws.  If  the  head  be  removed,  the  detached  por- 
tion will  then  live  for  nearly  an  hour  with  its  solitary  ganglion  ; 
it  will  set  in  motion  its  long  arms,  aud  knows  how  to  turn 
them  against  the  fingers  of  the  experimenter  who  holds  it, 
and  to  insert  its  hooks  in  them." 

If  we  descend  a  step  lower,  the  fundamentary  plurality  of 
the  animal  will  become  more  evident.  "  With  the  Annelids, 
each  ganglion  corresponds  to  a  segment  of  the  body,  often 
formed  of  many  rings,  as  for  instance,  with  leeches,  all  whose 
parts  are  repeated  with  every  five  rings.  Every  segment  thus 
possesses,  besides  this  ganglion,  a  similar  portion  of  the  prin- 
cipal apparatus,  sometimes  even  of  the  apparatus  of  the 
senses.  This  is  the  case  with  the  Polyophthalmus,  in  which 
each  segment  is  provided  with  two  rudimentary  eyes,  each 
receiving  a  nervous  thread  from  the  corresponding  ganglion, 
a  real  optic  nerve."  Each  of  these  segments  is  a  complete 


*  Vulpian,  op.   cit.   790.     Experiments  of  Duges,  Dujardin,  Walkenaer,  etc. 
Duges,  "  Physiologic  Comparee,"  i.  337. 


CHAP.  III.]        SELF  AND    THE   ORGANIZED  BODY.  203 

animal,  and  the  whole  animal  is  formed  "  of  several  element- 
ary animals  placed  one  after  another."  Thus  it  is  that,  when 
separated,  each  is  still  an  independent  centre  of  co-ordinated 
reflex  actions  adapted  to  an  end.  Now  the  only  difference 
between  a  nervous  system  so  constituted,  and  the  nervous 
system  of  a  mammal,  is  that  the  segments  of  the  first  are 
more  complete  and  independent  than  those  of  the  second. 
In  fact,  anatomy  shows  that  a  vertebral  column,  like,  an  annelid, 
is  composed  of  distinct  segments,  medullary  and  protecting, 
that  the  skull  itself  is  made  up  of  flattened  and  consolidated 
vertebrae,  and  that  the  brain  is  nothing  more  than  a  prolon- 
gation and  development  of  the  spinal  marrow.  In  short,  the 
republic  of  nervous  centres,  all  equal  and  almost  independant, 
which  we  meet  with  among  the  inferior  animals,  is  gradually 
changed  as  we  ascend  to  the  superior  animals,  into  a  monarchy 
of  unequally  developed  and  intimately  connected  centres 
subject  to  one  principal  centre. — But  this  advanced  organ- 
ization and  centralization  do  not  suppress  the  original  plurality 
of  the  being  so  constituted.  In  proportion  as  it  rises  in  the 
scale,  it  departs  from  the  state  in  which  it  was  a  total,  and 
approaches  the  state  in  which  it  will  be  an  individual ;  that  is 
all.  Even  when  in  the  state  of  an  individual,  we  can  push  it 
back  into  the  state  of  a  total ;  by  affecting  transverse  segments 
in  the  marrow  of  a  young  mammal,  it  is  possible,  if  circulation 
and  respiration  go  on,  to  maintain  in  it,  for  several  weeks,  in- 
dependent segments,  each  capable  of  reflex  action,  and  incapa- 
ble of  receiving  from  or  transmitting  to  others  any  excitation 
whatever.*  Lastly,  at  the  lowest  point  of  the  animal  scale, 
with  zoophytes  for  instance,  in  which  no  nervous  system  is  ap- 
parent, and  in  which  nervous  matter  probably  exists  in  a  dif- 
fused state  only,  the  pluralityand  division  are  much  greater  still; 
for  a  polypus  may  be  cut  in  every  direction,  and  even  chopped 
up  ;  each  fragment  becomes  complete,  and  furnishes  an  animal 
having  all  the  faculties  and  instincts  of  the  primitive  animal. 

The  reader  sees  now  how  the  web  of  events,  which  is  our- 
selves, and  of  which  we  have  consciousnesss,  is  connected 
with  the  rest.  This  series — which,  according  to  the  aspect  in 

*  See  ante  p,  184. 


204  OF  MENTAL  EVENTS.  [BOOK  IV. 

which  we  consider  it,  is  sometimes,  to  our  senses,  a  series  of 
molecular  movements,  sometimes,  to  our  consciousness,  a 
series  of  sensations,  more  or  less  transformed — is  nothing 
more  than  the  most  complex  and  most  predominant  in  a  group 
of  other  analogous  series.  In  proportion  as  we  descend  the 
animal  scale,  we  see  it  lose  its  domination  and  complexity, 
and  become  reduced  to  the  level  of  the  others,  while  these  in 
turn  loosen  their  mutual  connections,  and  become  insensibly 
degraded. — To  external  perception,  they  have  all  for  condi- 
tion of  existence,  the  integrity  and  renewal  of  the  nervous  sys- 
tem whose  special  activity  they  are,  and  the  beings,  more  or 
less  strictly  bound  together,  which  they  constitute,  whatever 
they  may  be  to  consciousness,  with  whatever  names  metaphy- 
sical or  literary  illusion  may  clothe  them,  are  subject  to  the 
same  condition. 


CHAP.  I.]  OF  ILLUSION.  20$ 


PART  THE  SECOND. 

THE  DIFFERENT  KINDS  OF  KNOWLEDGE. 


BOOK  I. 
OF  THE  GENERAL  MECHANISM  OF  KNOWLEDGE. 


CHAPTER  I. 

OF  ILLUSION. 

I.  The  reader  has  now  followed,  under  all  its  forms,  the 
internal  event  which  constitutes  our  knowledge.  Our  ideas 
are  signs,  that  is  to  say,  sensations  or  images  of  a  certain 
kind.  Our  images  are  repeated  surviving  and  spontaneously 
reviving  sensations,  that  is  to  say,  sensations  of  a  certain  kind. 
Our  sensations  strictly  so  called  are  whole  sensations,  made 
up  of  more  simple  sensations,  these  of  still  simpler  ones,  and 
so  on.  We  may,  then,  for  want  of  a  better  name,  say,  with 
Condillac,  that  the  internal  primordial  event  which  constitutes 
our  knowledge  is  sensation. — But  it  must  be  observed  that 
this  name  simply  denotes  its  most  remarkable  state,  that  in 
this  state  it  is  but  a  total  or  group  of  elementary  sensations, 
themselves  composed  of  more  elementary  sensations,  that  by 
the  side  of  these  are  other  rudimentary  ones,  equally  inacces- 
sible to  consciousness,  and  whose  presence  is  indicated  by  re- 
flex actions,  and  that  thus  the  internal  primordial  event  is 
progressively  simplified  and  degraded  to  an  infinite  extent  be- 
yond our  range  and  grasp.  We  must  further  observe,  to  un- 
derstand it  properly,  that  in  another  aspect,  that  is,  seen 
from  without  and  by  means  of  external  perception,  it  is  a  mo- 
lecular movement  of  the  nervous  centres,  and  so  comes  with- 


206  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I 

in  the  category  of  physical  phenomena.  We  must  finally  ob- 
serve that  the  names  of  force  and  substance,  of  self  and  mat- 
ter, denote  metaphysical  entities  only,  that  there  is  nothing 
real  in  nature  but  connected  webs  of  inter-connected  events, 
that  these  are  all  we  find  in  ourselves  or  in  other  things. — 

o 

This  is  why,  in  order  to  form  a  first  notion  of  mind,  we  must 
represent  to  ourselves  one  of  these  webs,  and  postulate  that, 
being  known  by  two  different  processes,  external  perception 
and  consciousness,  it  mnst  perforce  appear  under  two  irreduc- 
ible aspects  of  unequal  importance,  that  is  to  say,  moral  on 
the  face  and  physical  on  the  reverse. — The  primordial  event 
being  thus  disengaged  and  determined,  we  have  now  with  its 
combinations  to  construct  the  rest. 

We  are  conscious  of  our  states  of  mind,  we  recollect  them, 
we  forsee  many  of  them.  We  perceive  external  objects,  we 
recollect  their  changes,  we  forsee  many  of  them.  Besides  these 
operations,  which  are  common  to  us  with  animals,  there  are 
others,  special  to  ourselves.  We  form  abstractions  and  gen- 
eralizations, we  conclude,  we  reason,  we  construct  ideal  ob- 
jects. These  are  the  principal  groups  of  acts  which  make 
up  our  cognitions. — How  can  such  a  being  as  we  have  describ- 
ed accomplish  these  ? — How  can  they  be  constructed  out  of 
such  internal  events  as  we  have  described  ?  This  is  the  ques- 
tion, and  it  is  not  solved  by  saying,  as  many  psychologists  do, 
that  we  have  such  and  such  faculties,  consciousness,  memory, 
imagination,  or  reason.  These  are  verbal  explanations,  inher- 
ited from  the  school-men.  To  explain  one  of  these  acts  is  to 
distinguish  its  elements,  to  show  their  order,  to  determine 
the  conditions  of  their  origin  and  combination.  Now  the 
events  we  have  been  studying,  signs,  images,  sensations,  are 
the  elements  of  all  knowledge.  By  their  association  or 
their  conflict,  they  become  transformed.  On  the  one  hand, 
they  appear  other  than  they  are.  On  the  other  hand,  by  a 
more  or  less  complete  correction,  they  are  stripped  of  this 
false  appearance.  Two  principal  processes  are  employed  by 
nature  to  produce  the  operations  we  term  cognitions:  the 
one  consisting  in  the  creation,  of  illusions  within  us  ;  the  other 
consisting  in  their  rectification.  It  is  by  this  double  operation 
that  the  mental  edifice  is  raised  and  completed  ;  hitherto  we 


CHAP.  I.]  OF  ILLUSION.  2O/ 

have  been  observing  the  materials ;  now,  we  must  study  its 
structure. — Let  us  commence  at  once  with  examples ;  we 
shall  better  understand  the  meaning  of  the  words  by  first  see- 
ing the  particulars  of  the  facts. 

II.  A  woman  makes  violent  gestures,  wipes  her  eyes  with 
her  handkerchief,  and  sobs,  hiding  her  face  in  her  hands.  She 
cries  in  a  plaintive  voice : — "  Good  God  !  how  wretched  I  am  !  " 
Her  face  is  contracted,  her  chest  heaves,  she  is  panting,  and 
her  stifled  cries  are  incessantly  renewed. — She  is  acting  grief; 
but  if  I  happen  not  to  know  this,  it  seems  to  me  that  she  is  in 
great  grief;  which  means  that  her  gestures,  her  features,  cries, 
and  words  are  the  same,  and  arouse  in  me  the  same  ideas  as 
if  she  were  in  great  grief.  Between  her  grief  and  my  idea,  is 
a  series  of  intermediaries,  the.  first  of  which  is  her  expressive 
attitude.  This  attitude  is  usually  preceded  by  grief,  but  usu- 
ally only.  If  the  woman  is  a  skilful  actress,  the  grief  may  be 
wanting  though  the  attitude  is  there,  and  I  shall  form  the 
same  conclusion  as  if  the  grief  were  there. 

So  again,  a  stick  is  plunged  half-way  into  water ;  it  seems 
bent,  though  it  is  straight.  But  between  the  presence  of  the 
stick  and  my  preception  there  are  several  intermediaries,  the 
first  of  which  is  a  pencil  of  luminous  rays.  In  the  most  com- 
mon case,  that  is,  when  the  stick  is  wholly  in  the  air  or  whol- 
ly in  the  water,  if  the  rays  from  one-half  are  inflected  with  ref- 
erence to  the  rays  from  the  other  half,  the  stick  is  actually 
curved ;  but  this  Is  only  the  most  common  case.  When  by 
exception  the  straight  stick  is  plunged  into  two  unequally^ 
refracting  media,  although  it  is  straight,  the  rays  from  one- 
half  will  be  inflected  with  reference  to  the  rays  from  the 
other  half,  and  I  shall  have  the  same  perception  as  if  the  stick 
were  bent. 

Lastly,  take  the  case  of  a  person  who  has  lost  a  leg  and 
complains  of  tinglings  in  the  heel.  He  actually  experiences 
tinglings ;  but  not  in  the  heel  he  no  longer  possesses ;  only 
the  feeling  seems  to  be  there.  Here  again,  between  the  nerv- 
ous disturbance  in  the  heel  and  the  judgment  which  situates 
the  sensation  in  that  spot,  there  are  many  intermediaries 
the  principal  one  being  the  sensation  itself.  Usually,  when 
the  sensation  arises,  it  is  preceded  by  peripheral  disturbance, 


2o8  GENERAL  MECHANISM  OF  KNOWLEDGE.        [BOOK  I. 

but  usually  only.  When  by  exception  the  central  extremity 
existing  after  amputation  enters  into  activity,  the  sensation 
will  arise  though  the  heel  is  destroyed,  and  the  patient  will 
form  the  same  conclusion  as  when  he  still  had  his  leg. — These 
examples  show  us  very  clearly  in  what  the  appearance  con- 
sists. There  are  three  terms  forming  the  three  links  of  a 
chain ;  an  antecedent,  the  asserted  fact,  an  intermediary, 
which  is  usually  preceded  by  the  antecedent,  an  idea,  belief, 
judgment, or  perception,  which  always  follows  the  intermediary, 
and  refers  to  the  antecedent.  For  the  affirmative  judgment 
to  be  produced  it  is  sufficient  for  the  intermediary  to  be  pro- 
duced; it  matters  little  whether  the  antecedent  exists  or  not. 
To  push  this  further.  The  antecedent  has  been  hitherto 
simply  a  property  of  the  object,  sometimes  absent,  sometimes 
present ;  in  fact,  what  we  have  been  considering  has  been 
the  situation  of  a  tingling,  the  curvature  of  a  stick,  the  troub- 
le of  a  woman.  Let  us  now  look  for  a  case  in  which  the  an- 
tecedent is  the  object  itself;  this  is  what  happens  in  halluci- 
nations. A  man  sees,  with  eyes  closed  or  open,  the  perfectly 
distinct  head  of  a  corpse  three  paces  in  front  of  him,  though 
no  such  head  is  there.  This  means,  just  as  in  the  previous 
instances,  that  between  the  actual  presence  of  a  corpse's  head 
and  the  affirmative  perception,  are  a  group  of  intermediaries, 
the  last  of  which  is  a  particular  visual  sensation  of  the  nerv- 
ous centres.  Usually,  this  sensation  has  as  its  antecedents  a 
certain  molecular  motion  of  the  optic  nerves,  a  certain  im- 
pingement of  luminous  rays,  lastly,  the  presence  of  the  real 
head  of  a  corpse.  But  it  is  usually  only  that  these  three  ante- 
cedents precede'the  sensation.  If  the  sensation  is  produced  in 
their  absence,  the  affirmative  perception  will  arise  in  their  ab- 
sence, and  the  man  will  see  a  corpse's  head  which  is  not  ac- 
tually there.  Here  again,  the  presence  of  the  last  intermediary 
is  sufficient  to  cause  the  perception  to  arise ;  it  matters  little 
whether  the  antecedents  exist  or  not.  We  see  by  all  these 
examples  that  an  object  or  property  which  do  not  exist  seems 
to  us  to  exist,  when  the  final  effect  which  they  usually  pro- 
duce in  us  by  an  intermediary,  is  produced  in  us  without  their 
existence.  Their  intermediary  replaces  them  ;  it  is  equival- 
ent to  them. 


CHAP.  I.]  OF  ILLUSION. 


209 


Now  it  is  readily  seen  that  in  all  these  instances  the  final 
intermediary  which  immediately  precedes  the  affirmative  idea, 
belief,  perception,  or  judgment,  is  a  sensation.  The  others 
act  only  by  and  through  it.  Remove  all  but  it;  suppress 
the  thing  itself,  as  is  done  in  instruments  for  producing  optical 
delusions ;  suppress  the  luminous  rays,  which  is  what  happens 
in  the  cases  of  the  subjective  images  we  see  with  our  eyes 
closed  ;  suppress  the  disturbance  of  the  peripheral  extremity 
of  the  nerve,  which  happens  in  the  illusions  of  persons  who 
have  lost  limbs ;  suppress  all  action  of  the  nerve,  which  is 
what  happens  in  hallucination  strictly  so  called ;  leave  noth- 
ing subsisting  but  the  sensation  or  activity  of  the  centres  of 
sensation,  there  is  hallucination,  and  consequently  affirmative 
judgment. — On  the  contrary,  suppress  this  sensation  or 
activity  of  the  centres  of  sensation,  while  preserving  the 
other  intermediaries  and  the  object  itself;  let  there  be  an 
object  present,  and  in  the  light,  let  the  extremity  of  the 
nerve  be  in  action,  let  this  action  be  propagated  through  the 
whole  course  of  the  nerve ;  if  the  nervous  centres  are  be- 
numbed by  chloroform,  or  if,  as  happens  in  hypnotism  and 
in  impassioned  attention,  an  anterior  dominant  sensation 
closes  the  access  to  supervening  sensations,  a  drum  may  be 
beaten  in  the  room,  or  the  patient  may  be  pinched,  pricked, 
and  wounded  without  his  ever  surmising  it ;  as  he  does  not 
experience  the  sensation  of  sound,  or  the  pain  of  the  wound, 
he  will  perceive  neither  drum  nor  cutting  instrument.  In 
short,  in  the  absence  of  any  ulterior  obstacle,  it  is  necessary 
and  sufficient  for  the  production  of  the  perception  or  affirma- 
tive judgment  that  the  sensation  or  action  of  the  nervous 
centres  be  produced. — In  this  respect  mental  operations  re- 
semble vital  operations.  If  we  remove  the  tail  from  a  tad- 
pole and  throw  it  into  water,  it  will  become  organized  and 
developed  up  to  the  tenth  day,  just  as  if  it  had  remained  in 
its  first  place.*  If  we  cut  off  the  paw  of  a  young  rat,  and, 
having  skinned  it,  place  it  under  the  skin  of  the  side  of  an- 
other rat,  it  becomes  grafted  on,  is  nourished,  and  grows 


*  Vulpian,  296.     See  the  whole  thesis  of  Paul  Bert,  "  Sur  la  Vitalite  Propre 
des  Tissus  Animaux." 

i4 


2IO  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

there  and  acquires  its  full  development,  all  its  connections, 
all  its  ordinary  structure,  just  as  if  it  had  remained  attached 
to  its  former  owner.  Such  is  the  vital  process ;  in  the  ab- 
sence of  ulterior  obstacles,  that  is  to  say,  if  the  medium  be 
a  fitting  one,  it  goes  on  blindly,  whether  its  result  be  useful, 
useless,  or  even  harmful. — So  is  it  again  with  the  mental  pro- 
cess ;  in  the  absence  of  paralysis  or  other  hindrance  in  the 
cerebral  lobes,  as  soon  as  the  sensation  is  given,  the  affirma- 
tive perception  or  judgment  follows,  whether  false  or  true, 
salutary  or  pernicious,  matters  little,  even  should  the  hallu- 
cination which  sometimes  constitutes  its  lead  on  to  suicide, 
and  destroy  the  customary  harmony  adjusting  our  activity  to 
the  coarse  of  the  universe. 

III.  Thence  follows  a  consequence  of  capital  importance: 
it  is  that  external  perception  is  a  true  hallucination.  Let 
us  fully  understand  this  truth  in  the  guise  of  a  paradox.  A 
person  laboring  under  hallucination  who  sees  a  corpse's  head 
three  paces  in  front  of  him,  experiences  at  that  moment  an 
internal  visual  sensation  precisely  similar  to  what  he  would 
experience  if  his  open  eyes  were  then  to  receive  the  lumin- 
ous rays  coming  from  the  head  of  a  real  corpse.  There  is 
no  real  corpse's  head  in  front  of  him ;  there  are  no  gray  and 
yellowish  rays  coming  from  it ;  there  is  no  impression  made 
by  such  rays  on  his  retina,  or  transmitted  by  his  optic  nerves 
to  the  centres  of  sensation.  What  is  really  three  paces  in 
front  of  him  is  a  red  arm-chair ;  the  rays  coming  from  it  are 
red  ;  the  impression  made  on  his  retina  and  propagated  thence 
to  the  centres  of  sensation  is  one  of  red  rays.  But  never- 
theless, the  action  of  the  centres  of  sensation  is  that  which 
would  in  their  normal  state,  be  excited  in  them,  by  gray  and 
yellowish  rays,  such  as  an  actual  corpse's  head  would  emit. 
This  action  of  the  centres  of  sensation,  in  other  words,  this 
spontaneous  visual  sensation,  is  sufficient  to  call  up  in  him 
an  apparent  corpse's  head,  apparently  situated  three  paces 
off,  apparently  possessed  of  relief  and  solidity,  an  internal 
phantom,  but  so  closely  resembling  an  external  and  real  ob- 
ject that  the  patient  gives  a  cry  of  horror. — Such  is  the  effi- 
cacy of  the  visual  sensation  strictly  so  called ;  and  it  extends 
so  far  that  the  sensation  possesses  it  even  when  the  normal 


CHAP.  I.]  OF  ILLUSION.  211 

antecedents  are  absent.  It  extends  then  to  the  cases  in  which 
the  normal  antecedents  are  present ;  therefore  when  the 
corpse's  head  is  real  and  present,  when  a  pencil  of  gray  and 
yellowish  rays  starts  from  it  to  strike  the  retina,  when  this 
impression  of  the  retina  is  propogated  along  the  optic  nerves, 
when  the  action  of  the  centres  of  sensation  corresponds  to 
it,  the  visual  sensation  so  excited  will  give  rise  to  the  same 
internal  phantom,  and  the  semblance  of  the  corpse's  head, 
which  is  produced  in  us  during  hallucination,  properly  so 
called,  will  also  be  produced  in  us  during  external  perception, 
with  this  difference  only,  that,  in  the  first  case,  the  hand  or 
other  sense,  the  bystander  to  whom  we  appeal  to  attest  our 
affirmative  judgment,  will  pronounce  it  false,  whilst,  in  the 
second  case,  the  hand  or  other  sense,  the  bystander  to  whom 
we  appeal  to  test  our  affirmative  judgment,  will  confirm  it ; 
and  this  we  express  by  saying,  in  the  first  case,  that  the  ob- 
ject is  apparent  only,  and,  in  the  second  case,  that  it  is  real. 
It  is  readily  seen  that  this  analysis  is  applicable  not  only  to 
visual  sensations,  but  to  all  others,  since  all  the  others  admit 
of  hallucinations. — Therefore,  when  we  walk  in  the  street, 
watching  and  listening  to  what  passes  around  us,  we  have 
within  us  the  various  phantoms  which  would  be  experienced 
by  a  sufferer  from  hallucinations  shut  up  in  his  room,  and  in 
whose  case  the  visual,  auditory,  and  tactile  sensations  which 
are  produced  in  our  case  by  the  action  of  the  nerves  would 
all  be  produced  in  the  same  order  but  without  the  medium 
of  the  nerves.  These  various  phantoms  are  in  our  case,  as  in 
his,  houses,  roads,  carriages,  pavements,  and  passers-by.  Only, 
in  our  case,  there  are  objects  and  external  events,  indepen- 
dent of  ourselves  and  real,  proved  by  the  ulterior  experience 
of  the  other  senses,  and  by  the  concurring  testimony  of  other 
observers,  which  correspond  to  our  phantoms ;  while,  in  his 
case,  there  is  no  such  correspondence. — Thus,  external  per- 
ception is  an  internal  dream  which  proves  to  be  in  harmony 
with  external  things ;  and  instead  of  calling  hallucination  a 
false  external  perception,  we  must  call  external  perception  a 
true  hallucination.  Illness  separates  the  internal  event  and 
shows  it  us  as  it  is,  in  the  state  of  a  colored,  intense,  precise, 
and  localized  semblance.  In  this  state,  it  is  no  longer  con- 


212  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

fused  with  things  ;  we  can  distinguish  it  from  them,  and  im- 
mediately on  this  we  may,  with  fair  reason,  conclude  its 
presence  when  health  and  reason  are  perfect ;  hence  it  fol- 
lows that,  while  health  and  reason  are  perfect,  it  is  this  in- 
ternal event,  this  semblance  which  we  take  for  a  subsisting 
thing  other  than  ourselves  and  placed  without  us. 

By  the  same  stroke  we  comprehend  and  correct  the  error 
into  which  consciousness  naturally  falls  with  respect  to  exter- 
nal perception.  When  we  examine  our  perception  of  things 
without,  we  are  tempted  to  mistake  it  for  a  simple  naked  act 
of  mind,  destitute  of  any  sensible  character,  and  indeed  of  any 
character  other  than  its  relation  with  the  thing  which  is  its 
object. — Take  the  case  of  a  table,  I  see  it,  touch  it,  perceive 
it.  In  addition  to  my  tactile  and  visual  sensations,  I  find 
nothing  in  me  but  an  act  of  pure  attention,  a  spiritual  act, 
unique  in  kind,  incomparable  to  any  other. — There  is  nothing 
strange  in  this  conclusion  ;  if  the  act  is  pure  and  spiritual,  it  is 
because  it  is  empty ;  we  have  emptied  it  ourselves  by  taking 
from  it  all  its  characters,  to  set  them  apart  and  form  from 
them  an  object.  The  external  perception  of  an  arm-chair  is 
nothing  more  than  the  phantom  of  the  arm-chair ;  when,  in 
accordance  with  habit,  we  consider  this  phantom  as  a  real  and 
external  object,  we  cut  away  from  perception  all  that  consti- 
tutes it,  and,  from  a  full  act,  we  form  a  void  or  abstract  act. — 
We  have  already  seen  many  instances  of  this  illusion ;  we 
shall  see  many  more  such  ;  thus  arise  the  beings  and  spiritual 
activities  with  which  metaphysics  and  psychology  are  still 
crowded.  Many  philosophers,  and  all  those  who  content  them- 
selves with  words,  are  subject  to  this  error.  Usually  they 
picture  to  themselves  our  cognitions,  external  perceptions, 
recollections,  acts  of  consciousness  or  of  reason,  as  acts  of  a 
special  and  simple  nature,  of  which  we  are  unable  to  say  any 
thing  more  than  that  they  are  each  an  activity  and  a  relation, 
the  activity  of  a  simple  being,  which  by  their  means  enters  into 
relation  with  extended  beings  other  than  itself,  with  itself, 
with  past  events,  with  laws  or  higher  truths.  Science,  in  this 
acceptation  of  it,  is  soon  constructed  ;  there  is  nothing  to  seek 
or  to  find  in  an  activity  like  this,  since  it  is  simple  ;  when  once 
we  have  given  it  a  name  we  have  come  to  an  end.  The  truth 


CHAP.  I.]  OF  ILLUSION.  213 

is  we  have  found  names,  which  is  somewhat  unimportant. 
The  truth  again  is  that,  if  we  have  come  to  an  end  it  is  be- 
cause we  have  ourselves  barred  the  way.  Neither  external 
perception  nor  the  other  acquisitions  of  consciousness  are  sim- 
ple activities  applying  to  and  ending  in  objects  differing  from 
themselves.  They  are  symbols,  phantoms,  or  semblances* 
of  these  objects,  hallucinations,  usually  true,  and  arranged,  by 
an  artifice  of  nature,  in  such  a  way  as  to  correspond  to  objects, 
and  all  are  more  or  less  advanced,  retarded,  and  altered  in 
their  development.  We  shall  see  the  detail  and  the  arrange- 
ment in  the  following  pages. — Meanwhile  let  us  keep  in  mind 
this  principle,  that  sensation,  whether  in  the  absence  or  pres- 
ence of  impulsions  from  without  and  of  nervous  action,  produces 
hallucinations,  and  produces  them  by  itself  alone.  It  is  the 
motive  spring  of  all  the  mechanism,  and  so  much  so  that,  for 
the  purpose  of  renewing  and  perpetuating  our  knowledge, 
nature  has  given  it  a  substitute. 

IV.  This  substitute  is  the  image  ;  by  the  side  of  sensations 
strictly  so  called,  which  are,  by  nature,  temporary,  connected 
with  the  vibration  of  the  nerves,  almost  always  incapable  of 
reviving  spontaneously,  and  situated  in  the  centres  of  sensa- 
tion, there  is  another  series  within  us  of  absolutely  analogous 
events,  which  are,  by  nature,  durable,  which  survive  the  vibra- 
tion of  the  nerve,  are  capable  of  reviving  spontaneously,  and 
are  situated  in  the  cerebral  lobes  or  hemispheres.  These  are 
what  we  have  termed  images. — Here  are  a  second  group  of 
sensations,  so  similar  to  the  first  that  we  may  call  them  reviv- 
ing sensations,  and  repeating  the  first,  as  a  copy  repeats  an 
original,  or  as  an  echo  repeats  a  sound.  In  this  way  they 
have  the  properties  of  the  first,  they  replace  the  first  when 
absent,  and,  as  they  perform  the  same  function,  must  give  rise 
to  the  same  mental  process. 

This  is  what  experience  has  already  shown  us.  The  more 
complete,  that  is  to  say  the  more  intense  and  precise  do  they 

*  All  the  terms  by  which  men  have  denoted  the  phenomenon  result  etymologi- 
cally  in  the  same  meaning. — Conception  (cum-capere,  the  thing  becomes  internal). 
— Representation  (rursus  prsesens,  the  thing  present  anew  though  actually  absent). 
— Idea  (Eidos,  the  figure,  the  image,  the  semblance,  the  appearance  of  the  thing 
instead  of  the  thing  itself). — So  in  German,  Begriff,  Vorstellung,  &c. 


214  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

become,  the  more  does  the  operation  they  give  rise  to  border 
on  hallucination.  Represent  to  yourself  some  particular  ob 
ject  you  are  well  acquainted  with,  for  instance,  some  little 
brook  running  among  poplars  and  willows.  If  you  have  a 
clear  imagination,  and  permit  yourself  to  become  absorbed  in 
the  reverie  as  you  sit  by  the  fire,  you  will  soon  see  the  glis 
tening  waves  on  its  surface,  the  yellowish  or  ash-colored  leaves 
floating  down  its  stream,  the  little  eddies  agitating  the  water 
cresses,  the  cold  shade  of  the  lines  of  trees ;  you  will  almost 
hear  the  ceaseless  whispering  of  the  branches  and  the  vague 
rustling  of  the  water  striking  against  its  banks.  Fragments 
of  your  former  sensations  have  revived  in  you  ;  you  have  seen 
again,  with  closed  eyes,  patches  of  green,  of  blue,  of  dark  glit- 
ter ;  scraps  of  sound  have  come  back ;  and  these  surviving 
wrecks  of  the  primitive  sensation  have  had,  on  a  small  scale 
and  incompletely,  but  with  all  their  proportions  preserved, 
the  same  effect  as  the  primitive  sensation ;  the  hallucinatory 
process  has  been  half  effected. 

Let  us  get  rid  of  the  obstacles  which  hinder  its  completion. 
Let  us  take  the  case  of  the  images  which  present  themselves 
at  the  moment  the  waking  state  draws  to  a  close,  and  sleep 
begins.*  We  have  seen  that  they  become  brightened  and 
precise,  in  proportion  as  our  present  sensations  become  more 
and  more  vague  and  feeble ;  after  some  seconds  we  seem  to 
hear  real  sounds,  to  see  real  forms,  to  actually  smell,  taste, 
and  touch.  By  a  necessary  consequence,  affirmative  judg- 
ments follow  these  images ;  according  to  their  kind  we  think 
we  have  before  us  such  and  such  an  object,  "  an  open  book, 
printed  in  very  small  text  which  we  read  with  difficulty^  an 
hermaphrodite,  a  stew  with  mustard  in  it,  giving  out  a  very 
sharp  smell,  some  picture  of  Michael  Angelo,  a  lion,  a  green 
rhomboidal  figure,"  numbers  of  persons,  landscapes.  When 
sleep  has  actually  come  on,  the  hallucination,  then  at  its 
height,  makes  up  what  we  term  our  dreams. — When  the  sleep, 
instead  of  being  natural,  is  artificial,  the  hallucinatory  process 
becomes  plainer  still.  Such  are  the  cases  of  hypnotism  and 


*  Cf.  Maury,  "  Le  Sommeil,"  &c.,  p.  33. 
f  Maury,  ibid.  p.  51,  Observations  made  on  himself. 


CHAP.  I.]  OF  ILLUSION. 

somnambulism.  In  this  state,  which  may  be  excited  at  will 
in  many  persons,  the  patient  believes,  without  resistance  or 
reserve,  in  all  notions  suggested  ^  to  him,  and  these  may  be 
suggested  to  him  in  two  ways. 

The  first  means  of  suggestion  is  to  give  the  patient  an  at- 
titude which  would  correspond  with  some  particular  feeling, 
or  which  would  be  assumed  in  commencing  some  particular 
action,  or  which  would  indicate  the  presence  of  some  object ; 
he  will,  of  his  own  accord,  complete  the  attitude,  and  immedi- 
ately experiences  the  feeling,  goes  through  the  action,  and 
believes  in  the  presence  of  the  object. — If  the  head  be  thrown 
slightly  back,  and  the  spine  straightened,  "  his  countenance 
then  assumes  an  expression  of  the  most  lofty  pride,  and  his 
whole  mind  is  obviously  possessed  by  the  feeling."  At  this 
moment,  "  let  the  head  be  bent  forward,  and  the  body  and 
limbs  gently  flexed-;  and  the  most  profound  humility  then  takes 
its  place."  If  the  corners  of  the  mouth  be  gently  separated, 
he  becomes  lively  at  once  ;  and,  when  the  eyebrows  are  drawn 
towards  each  other,  and  downwards,  he  becomes  morose ; 
sometimes  on  waking  he  is  still  conscious  of  the  insurmounta- 
ble emotions  into  which  he  has  been  thrown  and  fixed  by  the 
ascendancy  of  the  attitude.  "  So,  again,"  says  Carpenter, 
"  not  merely  emotional  states,  but  definite  ideas  are  thus  ex- 
citable. Thus,  if  the  hand  be  raised  above  the  head,  and  the 
fingers  are  flexed  upon  the  palm,  the  idea  of  climbing,  swim- 
ming, or  pulling  at  a  rope  is  called  up ;  if,  on  the  other  h^nd, 
the  fingers  are  flexed  while  the  arm  is  hanging  down  at  the 
side,  the  idea  excited  is  that  of  lifting  a  weight ;  and  if  the 
same  be  done  when  the  arm  is  advanced  forwards  in  the  posi- 
tion of  striking  a  blow,  the  idea  of  fighting  is  at  once  aroused." 
The  somnambulist  proceeds  to  complete  the  action,  that  is 
to  say,  he  begins  to  box,  to  draw  up  his  arm  with  difficulty, 
to  move  his  limbs  as  if  to  climb,  to  swim,  or  to  pull  a  rope. 


\  Braid,  "  Neurhypnology." — Carpenter,  article  "  Sleep"  in  Todd's  "  Cyclopce- 
dia." — Dr.  Hack  Tuke,  "  De  la  Folie  Artificielle,"  "  Annales  Medico-Psychologi- 
ques,"  4"ie  Serie,  vi.  429,  and  vii. — Maury,  "  Le  Sommeil,"  &c. ;  the  whole  of  chap. 
II  and  p.  424. — Azam,  "Annales  de  Medecine  et  de  Chirurgie,"  Jan.,  1840 ;  and 
"  Annales  Medico-Psychologiques,"  3^10  Serie,  vi.  430. — Dr.  Philips,  "  Cours  de 
Braidisme,  theorique  et  pratique." 


2i6  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

The  second  means  of  suggestion  consists  in  words,  and 
this  process  sometimes  succeeds  in  ordinary  somnambulism. 
"  We  knew,"  says  Carpenter,  "  a  young  lady  at  school,  who 
frequently  began  to  talk  after  having  been  asleep  an  hour  or 
two  ;  her  ideas  almost  always  ran  upon  the  events  of  the  pre- 
vious day ;  and  if  encouraged  by  leading  questions  addressed 
to  her,  she  would  give  a  very  distinct  and  coherent  account 
of  them  ;  frequently  disclosing  her  own  peccadilloes  knd  those 
of  her  school-fellows,  and  expressing  great  penitence  for  the 
former,  whilst  she  seemed  to  hesitate  about  making  known 
the  latter.  To  all  ordinary  sounds,  however,  she  seemed  per- 
fectly insensible,  ....  and,  if  the  interlocutor  addressed  to 
her  any  questions  or  observations  that  did  not  fall  in  with 

her  train  of  thought,  they  were  completely  disregarded 

The  well-known  case  of  the  officer,  narrated  by  Dr.  James 
Gregory,  is  one  of  the  same  intermediate  class ;  rather  allied, 
in  our  apprehension,  to  somnambulism  than  to  ordinary  dream- 
ing. This  gentleman,  who  served  in  the  expedition  to  Louis- 
burgh  in  1^58,  was  in  the  habit  of  acting  his  dreams;  and 
their  course  could  be  completely  directed  by  whispering  into 
his  ear,  especially  if  this  was  done  by  a  friend  with  whose 
voice  he  was  familiar ;  so  that  his  companions  in  the  transport 
were  in  the  constant  habit  of  amusing  themselves  at  his  ex- 
pense.— At  one  time  they  conducted  him  through  the  whole 
progress  of  a  quarrel,  which  ended  in  a  duel ;  and  when  the 
parties  were  supposed  to  be  met,  a  pistol  was  put  into  his 
hand,  which  he  fired,  and  was  awakened  by  the  report. — On 
another  occasion  they  found  him  on  top  of  a  locker,  or  bunker, 
in  the  cabin,  when  they  made  him  believe  he  had  fallen  over- 
board, and  exhorted  him  to  save  himself  by  swimming.  He 
immediately  imitated  all  the  motions  of  swimming.  They 
then  told  him  that  a  shark  was  pursuing  him,  and  entreated 
him  to  dive  for  his  life.  He  instantly  did  so,  with  such  force 
as  to  throw  himself  entirely  from  the  locker  upon  the  cabin 
floor,  by  which  he  was  much  bruised,  and  awakened  of  course. 
— After  the  landing  of  the  army  at  Louisburgh,  his  friends 
found  him  one  day  asleep  in  his  tent,  and  evidently  much  an- 
noyed by  the  cannonading.  They  then  made  him  believe  that 
he  was  engaged,  when  he  expressed  great  fear,  and  showed 


CHAP.  I.]  OF  ILLUSION.  2I/ 

an  evident  disposition  to  run  away.  Against  this  they  re- 
monstrated ;  but,  at  the  same  time,  increased  his  fears,  by  imi- 
tating the  groans  of  the  wounded  and  the  dying  ;  and  when 
he  asked,  as  he  often  did,  who  was  down,  they  named  his  par- 
ticular friends.  At  last  they  told  him  that  the  man  next  him- 
self in  the  line  had  fallen,  when  he  instantly  sprung  from  his 
bed,  rushed  out  of  the  tent,  and  was  roused  from  his  danger 
and  his  dream  together  by  falling  over  the  tent-ropes. — After 
these  experiments  he  had  no  distinct  recollection  of  his 
dreams,  but  only  a  confused  feeling  of  oppression  and  fatigue  ; 
and  used  to  tell  his  friends  that  he  was  sure  they  had  been 
playing  some  trick  upon  him." 

Artificial  or  induced  somnambulism  puts  the  mind  into  a 
similar  state.  "  If  you  tell  a  somnambulist  that  you  are  a 
lion,  and  assume  something  of  its  attitude  by  going  on  all 
fours  and  imitating  its  roar,  the  magnetized  person  at  once 
exhibits  violent  fear,  which  appears  in  all  his  features,  and 
shows  all  the  signs  of  positive  conviction."*  When  a  person 
is  hypnotized,  says  Dr.  Tuke,f  he  may  often  "  be  made  be- 
lieve by  suggestion  that  he  sees  an  absent  person.  ...  So 
it  is  possible  to  make  him  imagine  that  he  hears  a  particular 
air  played  on  an  instrument,  while  really  there  is  no  sound 
produced."  Words  excite  in  the  patient  the  images  of  cer- 
tain auditory  or  visual  sensations,  and  the  mental  process 
which  ensues  is  precisely  the  same  as  if  the  sensations  them- 
selves had  been  aroused  through  the  medium  of  the  nerves. 

The  same  process  ensues  whatever  be  the  kind  of  the  im- 
ages. UC.  D.,  when  hypnotized,  was  asked  to  feel  the  oper- 
ator's fingers.  He  answered  that  he  felt  nothing.  The  oper- 
ator then  placed  his  finger  and  thumb,  joined  together,  under 
the  patient's  nose,  and  told  him  to  draw  in  his  breath,  so  as 
to  take  a  pinch  of  snuff.  The  suggestion  took  effect  at  once. 
The  patient  drew  in  his  breath,  and  then  showed  all  the  symp- 
toms consequent  on  taking  a  sternutatory  powder." — And 
so,  "  tell  a  person  properly  prepared  by  hypnotism  that  he  is 

*  Maury,  333.  I  have  myself  watched  analogous  experiments  at  the  house  of 
Dr.  Fuel.  A  somnambulist  was  told  that  she  was  in  a  garden  ;  she  went  through 
the  motion  of  plucking  flowers  and  smelling  them  with  great  pleasure. 

f  "  Annales  Medico-Psychologiques,"  4™e  Serie,  vi.  427  :  and  vii.  261. 


2i8  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

eating  rhubarb,  that  he  is  chewing  tobacco,  or  some  other  sub- 
stance of  unpleasant  taste,  ....  and  the  effect  will  follow 
the  words.  Thus,  one  W.  H.  was  hypnotized,  and  a  glass  of 
pure  water  placed  before  him,  which  he  was  induced  to  take 
as  brandy.  He  praised  it  as  excellent — the  water  had,  in  fact, 
for  him  the  taste  of  brandy — and  drank  it  eagerly,  asking  for 
another. — In  the  second  instance,  J.  K.,  when  in  the  same 
abnormal  state  was  asked  to  drink  a  little  fresh  water,  and, 
while  he  did  so,  the  operator  drank  a  little  of  it  himself,  and 
spat  it  out  at  once  with  an  expression  of  horror  and  disgust. 
This  action  suggested  at  once  to  the  patient  that  the  water 
.was  impure  or  perhaps  poisoned,  so  much  so  that  in  this  per- 
suasion he  spat  it  out  with  disgust." — The  same  illu- 
sion occurs  when  the  image  suggested  is  that  of  a  sensation 
of  touch.  "  C.  D.  was  hypnotized,  and  induced  to  believe 
that  he  was  covered  with  bees.  He  gave  credence  to  the 
suggestion  at  once,  and  acted  precisely  as  a  person  would  do 
when  stung.  He  gave  all  the  signs  of  pain,  shook  his  hair, 
rubbed  his  face  with  his  hands  in  a  frantic  manner,  and  then 
tore  off  his  coat  to  rid  himself  of  his  imaginary  assailants. 
He  was  evidently  laboring  under  an  hallucination  of  general 
sensibility. — The  same  thing  may  be  said  of  another  person, 
E.  F.,  who,  under  the  same  conditions  of  somnambulism,  was 
led  by  suggestion  to  believe  that  she  suffered  from  a  violent 
toothache,  the  operator  increasing  the  effect  of  his  words  by 
placing  his  finger  on  the  patient's  cheek,  when  she  buried  her 
face  in  her  hands,  and  moved  from  side  to  side,  writhing  with 
pain." 

In  all  these  instances,  the  physical  and  moral  conditions 
which  usually  repress  the  hallucinatory  process  are  absent. 
In  fact,  the  nerves  and  centres  of  sensation  are  benumbed ; 
all  that  portion  of  the  nervous  system  by  which  we  commu- 
nicate with  the  outer  world  becomes  inactive,  or  compara- 
tively so.  When  this  happens,  we  have,  in  fact,  no  sensations 
strictly  so  called,  or  at  all  events  those  which  we  have  are  sin- 
gularly blunted,  and  are  of  no  effect  as  far  as  we  are  concern- 
ed. They  all  cease  in  the  case  of  the  ordinary  sleeper;  with 
the  dreamer  those  only  subsist  which  harmonize  with  his 
dreams  ;  the  somnambulist  and  hypnotized  person  preserve  a 


CHAP.  I.]  OF  ILLUSION.  2 19 

series  of  them  only,  those  termed  muscular  or  those  of  the 
sounds  put  before  him  by  the  operator.  Sensations  thus  lose 
wholly  or  in  part  the  control  they  exercise  in  the  normal 
state. — In  physiological  language  the  equilibrium  subsisting 
in  the  waking  state  between  the  nerves  and  nervous  centres 
on  the  one  side,  and  the  hemispheres  on  the  other,  is  upset 
in  favor  of  the  hemispheres  ;  they  perform  their  functions 
alone,  and  in  a  preponderating  manner.  In  psychological  lan- 
guage the  equilibrium  subsisting  in  the  waking  state  between 
sensations  and  images  is  upset  in  favor  of  the  images ;  they 
acquire  their  full  development  and  all  their  consequences  ;  they 
become  intense  and  precise,  result  in  affirmative  judgments, 
produce  the  same  mental  process  as  sensations  themselves, 
and  give  rise  to  hallucinations.  ' 

V.  An  important  consequence  follows  from  this.  We 
have  seen  that  in  every  representation,  conception,  or  idea, 
there  is  an  image  or  a  group  of  images. — When  I  think  of 
any  particular  object,  the  Louvre  for  instance,  there  is  some 
image  in  my  mind  of  the  visual  sensation  I  should  have  in  its 
presence. — When  I  think  of  a  general  object,  the  tree  or  the 
animal,  there  is  some  fragment,  more  or  less  vague,  in  my 
mind  of  an  analogous  image,  and,  in  every  case,  the  image  of 
its  name,  that  is  to  say,  the  visual,  auditory,  muscular  sensa- 
tions, which  the  name  would  excite  in  me  if  I  read,  pro- 
nounced, or  heard  it. — Consequently,  in  all  the  higher  opera- 
tions we  effect  by  means  of  abstract  names — judgment,  rea- 
soning, abstraction,  generalization,  combination  of  ideas — 
there  are  images  more  or  less  effaced  or  more  or  less  distinct. 
— On  the  other  hand  it  is  evident  that  all  recollections  and  all 
previsions  contain  images.  When  I  recollect  that  the  sun 
rose  yesterday  at  a  particular  point  of  the  horizon,  and  when 
I  predict  that  it  will  rise  to-morrow  at  some  other  particular 
point,  I  have  internally  the  image,  vague  or  distinct,  of  the 
visual  sensation  which  I  had  yesterday,  and  the  visual  sensa- 
tion I  shall  have  to-morrow. — And  so  again,  all  the  associated 
perceptions  which  recollection  and  prevision  add  to  the  crude 
sensation  to  constitute  ordinary  external  perception,  all  the 
judgments,  beliefs,  and  conjectures  which  a  simple  sensation 
excites  as  to  the  distance,  form,  kind,  and  properties  of  objects, 


220  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

contain  images.  This  arm-chair,  three  paces  from  me,  gives 
my  eyes  the  sensation  only  of  a  green  patch,  differently  shaded, 
according  to  its  different  parts ;  still,  from  this  simple  visual 
indication,  I  conclude  that  it  is  solid,  soft,  with  a  certain  mag- 
nitude and  form,  and  that  I  may  seat  myself  in  it ;  in  other 
words,  I  imagine  the  certainty  of  a  series  of  muscular  and 
tactile  sensations  which  my  hands  and  body  would  have,  if  I 
were  to  make  the  experiment. — Lastly,  in  consciousness  itself, 
for  instance,  in  the  consciousness  of  our  present  sensations, 
there  are  images  ;  for,  when  we  are  conscious  of  a  pain,  a 
taste,  a  muscular  effort,  a  sensation  of  cold  or  heat,  we  situ- 
ate it  at  some  spot  or  other  of  our  organs  or  limbs ;  in  other 
words,  my  sensation  arouses  the  image  of  the  tactile,  visual, 
and  muscular  sensations  of  which  I  should  avail  myself  to  rec- 
ognize the  spot  at  which  the  nervous  disturbance  is  produced. 

Thence  it  follows  that  all  these  operations  comprise  an 
hallucination,  at  all  events  in  an  incipient  state.  The  image, 
a  spontaneous  repetition  of  the  sensation,  tends  like  it  to 
excite  an  hallucination.  No  doubt  it  does  not  fully  excite 
it ;  the  mental  process  which  has  commenced  is  checked  by 
surrounding  repressions ;  the  image  must  be  alone  and  left 
to  itself,  as  in  sleep  and  hypnotism,  to  attain  its  full  develop- 
ment and  produce  its  whole  effect ;  it  does  this  in  part  only ; 
when  it  does  so  completely  the  man  is  mad. — But  whether 
the  hallucinatory  process  be  commenced  or  completed  mat- 
ters little,  and  the  state  of  our  mind  when  we  are  awake  and 
in  health  may  be  defined  as  a  series  of  hallucinations  which 
do  not  become  developed. 

Let  us,  in  fact,  consider  our  usual  representations  and  the 
habitual  tenantry  of  our  brain :  let  us  picture  to  ourselves 
some  house,  some  street,  some  study,  some  drawing-room, 
certain  human  figures,  certain  sounds,  smells,  tastes,  feelings 
of  contact,  muscular  efforts,  and,  above  all,  certain  words ; 
these  last  read,  heard,  or  pronounced  mentally,  form  most 
numerous  inmates  of  a  thinking  brain.  All  are  phantoms  of 
external  objects,  semblances,  of  action  and  sensation,  recog- 
nized on  the  spot  as  simple  appearances,  and,  moreover,  fugi- 
tive, effaced,  incomplete,  but,  on  the  whole,  identical  in  nature 
with  the  phantom  of  the  house  or  of  the  corpse's  head  arising 


CHAP.  I.]  OF  ILLUSION.  221 

in  a  person  suffering  from  hallucination,  with  the  semblance 
of  cutaneous  stings  or  of  nasal  tingling  arising  in  the  hypnotized 
person  or  somnambulist.  Between  the  idea  and  the  halluci- 
nation there  is  no  other  difference  than  that  between  the 
germ  and  the  full-grown  vegetable  or  animal. 

We  have  but  to  look  at  cases  of  mental  disease  to  see  the 
germ  develop  itself,  and  obtain  the  proportions  denied  it  in 
the  normal  state.  Let  us  examine  in  turn  the  words  and 
images  which  make  up  our  ordinary  thoughts. — In  the  normal 
state  we  think  by  words  mentally  heard,  read,  or  pronounced, 
and  what  passes  through  our  minds  are  images  of  certain 
sounds,  certain  letters,  or  certain  muscular  and  tactile  sensa- 
tions of  the  throat,  the  tongue,  and  the  lips. — Now  it  is  suffi- 
cient for  these  images,  and  especially  for  the  first  of  them,  to  be- 
come exaggerated  for  the  patient  to  have  hallucinations  of 
hearing,  and  to  believe  that  he  hears  voices. — "  In  the  midst  of 
my  fever,"  says  Mme.  C.,*  "  I  perceived  a  spider  hanging 
from  the  ceiling  over  my  bed.  A  mysterious  voice  told  me 
to  catch  the  spider.  As  I  was  afraid  of  the  insect,  I  caught 
it  with  the  corner  of  the  sheet.  After  many  efforts  I  rose, 
and  received  an  order  to  burn  the  spider  and  the  sheet  to  de- 
liver myself  from  sorcery,  so  I  set  fire  to  the  sheet.  My  room 
then  became  filled  with  a  thick  smoke.  A  mysterious  voice 

told  me  to  leave  it  as  quickly  as  I  could Having  walked 

about  the  streets  for  three  or  four  hours,  I  heard  the  mysterious 
voice,  as  I  passed  a  pastrycook's,  telling  me  to  buy  a  cake,  and  I 
did  so.  Further  on,  near  a  drinking  fountain,  /  was  ordered  to 
drink.  I  bought  a  glass  and  drank."  Some  hours  afterwards 
she  found  herself  near  the  Baths  in  the  Rue  Vendome ;  the 
mysterious  voice  commanded  her  to  take  a  bath  ;  but  this  same 
voice  proceeded  with  so  much  force  from  the  bath  that  Mme. 
C.  was  frightened,  and  left  without  venturing  into  the 
water. — "  M.  N.  was  prefet  of  a  large  town  in  Germany 
which  rose  in  1812  against  the  rearguard  of  the  French  army, 
then  in  retreat."  His  mind  was  upset  by  this ;  he  imagined 
himself  accused  of  treachery  and  dishonored  ;  in  short,  he  cut 
his  throat  with  a  razor.  "  As  soon  as  he  regained  his  senses  he 


*  Baillarger,  "  Des  Hallucinations,"  p.  14-24,  &c. 


222  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BoOK  I. 

heard  voices  accusing  him  ;  when  cured  of  his  wound  he  heard 

the  same  voices These  voices  repeated  to  him  night  and 

day  that  he  had  betrayed  his  trust,  that  he  was  dishonored, 
that  the  best  thing  he  could  do  was  to  kill  himself.  They 
availed  themselves  in  turn  of  all  the  languages  of  Europe 
which  the  patient  knew  ;  only,  one  of  these  voices  was  heard 
less  distinctly  than  the  rest,  as  it  employed  the  Russian 
language,  which  M.  N.  spoke  less  readily  than  the  others. 
M.  N.  frequently  retired  alone,  the  better  to  hear  and  listen  ; 
he  asked  questions,  he  replied,  he  became  convinced  that  his 
enemies  by  some  means  or  other  could  guess  his  inmost  thoughts. 
....  On  other  matters  he  reasoned  perfectly  correctly,  all 
his  intellectual  faculties  were  unimpaired,  he  followed  conver- 
sations on  various  subjects  with  the  same  spirit,  knowledge, 

and  readiness  as   before  his   illness Having  returned 

home,  M.  N.  passed  the  summer  of  1812  in  a  country  house, 
where  he  received  a  great  deal  of  company.  When  conver- 
sation became  interesting  he  heard  no  voices ;  if  it  slackened 
he  heard  them  imperfectly;  if  he  left  the  company  and  retired 
alone  the  better  to  hear  what  these  perfidious  voices  said,  he 
became  disquieted  and  anxious." — These  hallucinations  per- 
sisted some  time  after  his  reason  had  returned,  but  they  were 
no  longer  continuous,  and  usually  occurred  in  the  morning 
only,  soon  after  rising.  "  My  patient,"  says  Esquirol,  "  had  his 
attention  distracted  from  them  by  a  very  short  conversation 
or  reading ;  but  now  he  knew  as  I  did  what  these  symptoms 
were  ;  he  looked  on  them  as  a  nervous  phenomenon,  and 
expressed  his  surprise  at  having  been  their  dupe  so  long." 
— "  Nothing  is  more  common,"  adds  M.  Baillarger,  "  than 
to  hear  patients  complain  that- their  invisible  interlocutors 

tell  them  a  host  of  things  about  their  own  affairs To 

employ  the  expression  of  a  patient,  '  How  can  they  read  in 
one's  life  as  in  a  book  ?  ' ' 

Not  only  may  the  image  of  articulate  sound,  that  is  to 
say,  of  words,  but  every  image  of  sound  may  be  developed 
so  as  to  become  an  internal  sensation.*  "In  1831,  during  an 
outbreak,  the  wife  of  a  workman,  then  eight  months  preg- 


*  Baillarger,  "  Des  Hallucinations,"  p.  9. 


CHAP.  I.]  OF  ILLUSION.  223 

nant,  saw,  as  she  was  attempting  to  reach  her  home,  her  hus- 
band fall  mortally  wounded  by  a  bullet ;  she  was  delivered  of 
a  child :  ten  days  afterwards  delirium  set  in  ;  she  heard  the 
noise  of  cannon,  the  fire  of  musketry,  the  whistling  of  bullets, 
and  fled  into  the  country.  She  was  brought  to  the  Salpfitri- 
ere,  and  recovered  in  about  a  month."  In  the  next  ten  years 
six  similar  attacks  occurred,  and  in  each  case  the  same  hallu- 
cinations were  renewed  from  the  outset  of  the  delirium. 
"  The  patient  on  each  occasion  escaped  into  the  country  to 
avoid  the  noise  of  cannon  and  musketry,  and  the  crashing  of 
windows  broken  by  the  shot." — In  a  healthy  brain  the  image 
of  the  sounds  heard  in  the  outbreak  would  have  been  exact- 
ly reproduced,  but  very  faintly.  It  might  have  been  driven 
away  and  recalled  at  will.  By  these  two  characters  it  would 
have  been  recognized  as  purely  internal,  and  would  have  been 
distinguished  from  sensation.  Here  it  was  reproduced  with 
an  intensity  equal  to  that  of  the  sensation  and  unexpectedly, 
without  act  of  will,  even  against  the  resistance  of  the  will ; 
thus  it  no  longer  differed  from  the  sensation,  as  we  are  ac- 
quainted with  it  by  consciousness.  Therefore,  it  had  the  same 
effects  and  same  consequences,  and  renewed  the  trouble  and 
terror  which  the  woman,  then  sound  in  mind,  had  experienced 
during  the  fighting. 

The  same  observation  is  to  be  made  as  to  other  images, 
and  especially  as  to  those  of  sight.  A  lady  was  in  great  trou- 
ble at  the  loss  of  her  husband,  and,  being  a  believer  in  the  im- 
mortality of  the  soul,  constantly  thought  of  him  as  of  a  per- 
son still  in  existence.  "  One  evening,  just  as  she  was  going 
to  bed,  there  being  a  faint  light  in  the  room,  she  saw  her  hus- 
band cautiously  approaching  her,  heard  him  pronounce  some 
words  in  a  low  tone,  and  felt  her  hand  pressed  by  that  of  the 
departed."  Full  of  doubt  and  surprise  she  held  her  breath, 
the  phantom  disappeared,  and  she  found  she  had  been  the 
dupe  of  an  hallucination. — "  Two  persons,"  says  Griesinger, 
"  shortly  before  an  outbreak  of  madness,  had  been  much  given 
to  hunting.  In  their  cases,  the  delirium  turned  principally 
on  the  adventures  of  the  chase.  Another  had  been  read- 
ing, shortly  before  falling  ill,  an  account  of  travels  in  the  Him- 
alayas, and  it  was  on  this  subject  that  his  delirium  chiefly 


224  GENERAL  MECHANISM  OF  KNOWLEDGE.        [BOOK  I. 

turned." — The  most  obliterated  circumstances*  of  our  early 
years,  the  least  observed  and  most  insignificant  incidents  of 
our  life,  occasionally  revive  with  this  monstrous  hypertrophy. 
"  I  passed  my  early  life  at  Meaux,"  says  M.  Maury,  "and  of- 
ten went  to  a  neighboring  village  called  Trilport,  situated  on 
the  Marne,  where  my  father  was  building  a  bridge.  One 
night,  in  a  dream,  I  found  myself  carried  back  to  the  days  of 
childhood,  and  playing  in  this  village  of  Trilport.  I  saw  a 
man  dressed  in  a  kind  of  uniform,  and  spoke  to  him  and  asked 
his  name.  He  told  me  he  was  called  C.,  and  that  he  was 
coast-guard  there,  then  disappeared  to  give  place  to  other 
persons.  I  woke  up  with  a  start,  having  the  name  C.  in  my 
head.  Was  this  a  pure  imagination,  or  was  there  really  at 
Trilport  a  coast-guard  named  C.  ?  I  did  not  know,  having 
no  recollection  of  such  a  name.  Some  time  afterwards,  I 
questioned  an  old  servant  who  formerly  lived  with  my  father, 
and  who  had  often  taken  me  to  Trilport.  I  asked  her  if  she 
recollected  a  person  of  the  name  of  C.,  and  she  told  me  at 
once  that  he  had  been  a  coast-guard  of  the  Marne,  when  my 
father  was  building  the  bridge.  Most  certainly  I  had  known 
this,  as  she  did,  but  the  recollection  had  become  effaced.  The 
dream  in  calling  it  up  had  as  it  were  revealed  to  me  what  I 
did  not  know." — So  again,  Theophile  Gautier  tells  me  that 
once  passing  before  the  Vaudeville  he  read  upon  the  placard, 

"  the  polka  will  be  danced  by  M ."     This  phrase  fastened 

itself  to  him,  and  he  thought  of  it  incessantly,  and  in  spite  of 
himself,  by  an  automatic  repetition.  After  some  time  it  was 
no  longer  a  single  mental  phrase,  but  a  phrase  composed  of 
articulate  sounds,  and  with  an  external  tone  and  appearance. 
This  lasted  several  weeks,  and  he  began  to  get  uneasy,  when 
suddenly  the  besetting  disappeared. — There  is  no  normal  im- 
age, even  the  most  ancient,  the  most  enfeebled,  the  most  la- 
tent, which  may  not  vegetate  and  develop  in  this  manner, 
just  as  there  is  no  grain  of  poppy-seed,  the  most  insignifi- 
cant, the  most  abandoned  to  hazard,  which  may  not  become 
a  poppy. 

*  A  number  of  instances  are  collected  by  M.  Maury.  "  Le  Sommeil,"  &c.,  pp. 
70,  120,  128. — See  other  remarks  as  to  images  which,  on  reviving,  become  halluci- 
nations, in  De  Quincey,  "  Confessions,  &c.,"  p.  258. 


CHAP.  I.]  OF  ILLUSION.  22$ 

For  this  reason,  if  we  wish  to  understand  the  mental  pro- 
cess excited  by  the  image  in  its  reduced  and  abortive  state, 
we  must  examine  the  mental  process  excited  by  it  in  its  state 
of  fulness  and  freedom.  We  must  imitate  the  zoologists, 
who,  to  explain  the  structure  of  some  useless  bony  excres- 
cence, prove  by  the  comparison  of  neighboring  species  that  it 
is  a  rudimentary  limb ;  or  the  botanists,  who,  by  increasing 
•the  nourishment  of  a  plant,  change  its  stamens  into  petals, 
and  so  prove  that  the  ordinary  stamen  is  an  altered  and  abor- 
tive petal. — By  similar  comparisons,  and  from  analogous  hy- 
pertrophies, we  discover  that  the  image,  like  the  sensation  it 
repeats,  is,  in  its  nature,  hallucinatory .  Thus  the  hallucina- 
tion, which  seems  a  monstrosity,  is  the  very  fabric  of  our  men- 
tal life. — Considered  in  relation  to  things,  sometimes  it  cor- 
responds with  them,  and  then  constitutes  normal  external 
perception  ;  sometimes  it  does  not  so  correspond,  and  then, 
as  for  instance,  in  dreams,  somnambulism,  hypnotism,  and  dis- 
ease, it  constitutes  false  external  perception,  or  hallucination 
strictly  so  called. — Considered  in  itself,  sometimes  it  is  com- 
plete and  perfectly  developed,  as  happens  in  the  two  prece- 
ding cases ;  sometimes  it  is  repressed,  and  remains  in  a  rudi- 
mentary state ;  as  happens  in  the  cases  of  ideas,  conceptions, 
representations,  recollections,  previsions,  imaginations,  and  all 
the  rest  of  the  operations  of  the  mind. 
15 


226  GENERAL  MECHANISM  OF  KNOWLEDGE.    [CHAP.  II. 


CHAPTER  II. 

OF   RECTIFICATION. 

I.  IT  now  remains  for  us  to  study  this  abortion  and  its 
different  stages.  The  reader  must  here  revert  to  the  theory 
before  explained  of  antagonist  reductives.* — When  alone,  and 
in  silence,  reclining  in  a  chair,  I  abandon  myself  to  reverie, 
and  when,  by  the  obliteration  of  ordinary  sensations,  the  in- 
ternal phantasmagoria  becomes  intense,  if  sleep  draws  on,  my 
precise  images  end  by  exciting  actual  hallucinations.  At  this 
moment  a  slight  touch  arouses  me,  the  images  become  un- 
done ;  the  imaginary  sounds  lose  their  tone  and  sharpness ; 
the  colors  fade ;  the  outlines  become  vague,  and  the  hallu- 
cinatory process  is  proportionately  checked ;  the  landscapes, 
houses,  and  figures  I  dreamed  of  are  only  seen  imperfectly 
and  through  a  mist ;  they  seem  to  lose  their  solidity  and  con- 
sistence.— So  far,  there  is  nothing  remarkable.  We  knew 
that  the  two  great  departments  of  the  nervous  system,  that 
in  which  sensations  take  effect,  and  that  producing  images, 
are  antagonistic — in  other  words,  that  sensations  become  fee- 
ble as  images  become  strong,  and  vice  versd, ;  from  which  it 
follows  that  the  waking  state,  as  it  draws  to  a  close,  confers 
the  ascendancy  on  images  by  taking  it  from  sensations,  and 
that  the  close  of  sleep  deprives  images  of  their  ascendancy  by 
restoring  it  to  sensations. — But  here  a  new  phenomena  is  dis- 
closed :  not  only  does  the  phantom  grow  pale,  but  it  ceases 
to  appear  a  real  object.  It  was  pronounced  external,  it  is 
pronounced  internal.  While  we  preserve  our  mental  health, 
we  recognize  the  figure  for  what  it  is — that  is  to  say,  for  a 
simple  phantom,  a  pure  semblance,  a  representation,  an  idea. 
And  this  recognition  is  made,  even  when  it  remains  precise, 


*  Part  I.  hook  ii.  chap.  i.  pp.  53  et  seq. 


CHAP.  II.]  OF  RECTIFICA  TION. 

colored,  possessed  of  relief,  founded  on  intact  images.  In 
fact,  those  painters  who  have  the  clearest  imagination,  those 
who  paint  a  whole  portrait  from  memory* — Horace  Vernet, 
who  painted  elaborate  uniforms  from  his  head — are  not  sub- 
ject to  hallucinations  ;  they  do  not  confound  their  mental  rep- 
resentations with  external  objects ;  with  exceptions,  they  all 
declare  that,  as  far  as  they  are  concerned,  these  representa- 
tions are  invariably  mental. — Here,  in  fact,  comes  into  play  a 
mechanism  of  universal  application  in  our  intelligence.  A 
general  law  governs  all  our  representations,  from  the  most  ab- 
stract to  the  most  sensible.  We  cannot  conceive  a  figure  as 
having  three  sides  and  at  the  same  time  as  having  four.  We 
cannot  imagine  a  surface  as  blue  and  at  the  same  time  as  red. 
We  cannot  perceive  our  right  hand  as  hot  and  at  the  same  time 
as  cold.  When  two  contradictory  representations  come  in  con- 
tact, the  first  is  altered  by  the  second,  and  this  alteration  con- 
stitutes what  we  call  in  ordinary  language  a  partial  negation. 
The  two  together  thus  form  a  complex  representation,  with 
two  periods:  in  this  compound  the  second  negatives  the  first, 
on  one  point  or  another;  and  the  alteration  so  produced  va- 
ries in  magnitude  and  differs  in  nature,  according  to  the  kind 
of  the  two  representations  thus  united  and  in  conflict. 

Observe  the  simplicity  of  the  mechanism.  It  consists 
solely  in  the  attachment  of  a  contradictory  representation. 
By  this  attachment,  the  first  become  affected  by  a  negation — 
in  other  words,  contradicted  in  some  particular  respect,  some- 
times as  an  external  and  real  object,  sometimes  as  an  actual 
or  present  object,  and  this  operation  causes  it  to  appear,  some- 
times as  an  internal  and  imaginary  object — that  is  to  say,  as 
a  simple  representation  and  pure  phantom — sometimes  as  a 
past  or  future  event — that  is  to  say,  as  a  recollection  or 
prevision. 

II.  To  convince  ourselves  of  this,  let  us  consider  some  ex- 
amples, those  which  served  to  explain  the  appearance  will  also 
serve  to  explain  the  rectification. — Take  the  case  of  a  clever 
actress  imitating  grief;  in  her  presence  we  almost  attain  il- 
lusion ;  an  unaccustomed  or  impassioned  spectator  actually 


*  The  testimony  of  Horace  Vernet  himself. 


228  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

attains  it ;  as,  for  instance,  the  American  soldier  on  guard  at 
the  theatre  when  Othello  was  played,  who  cried  out,  "  It  shall 
never  be  said  that  a  wretched  negro  killed  a  white  woman 
while  I  stood  by ; "  on  which  he  levelled  his  piece  at  the  ac- 
tor, and  put  a  ball  through  his  arm. — We  are  not  carried  away 
to  this  extent,  but  when  a  play  is  very  good,  in  close  imita- 
tion of  modern  life,  and,  especially,  at  a  first  representation, 
suppressed  exclamations,  involuntary  laughter,  a  hundred 
little  gestures,  show  the  emotion  of  the  audience.  The  rea- 
der may  observe  this  in  himself  when  he  sees  for  the  first  time 
some  new  comedy  of  Dumas  the  younger ;  twenty  times  in 
an  act  we  have  a  minute  or  two  of  complete  illusion ;  some 
true,  unexpected  phrase,  supported  by  the  appropriate  ges- 
ture, accent,  and  surroundings,  leads  us  up  to  it.  We  are 
distressed  or  enlivened ;  we  are  on  the  point  of  rising  from 
our  seats ;  then,  of  a  sudden,  the  sight  of  the  footlights,  of 
the  audience  at  the  side,  some  other  incident,  recollection,  or 
sensation,  stops  us  and  keeps  us  in  our  place.  Such  is  the 
illusion  of  the  theatre,  incessantly  upset  and  reviving;  in  this 
the  pleasure  of  the  spectator  consists.  His  emotions  of  pity 
and  aversion  would  be  too  powerful,  if  they  lasted  ;  their 
sharpened  point  is  blunted  by  incessant  rectification.*  At 
one  moment  he  believes,  then  he  ceases  to  believe  ;  then 
again  begins  to  believe,  then  again  ceases  to  believe ;  each 
of  these  acts  of  belief  ends  in  a  denial,  and  each  of  these  bursts 
of  sympathy  culminates  in  an  abortion ;  thus,  a  series  is  made 
up  of  checked  beliefs  and  weakened  emotions;  we  say,  in  turn, 
"  Poor  woman,  how  unfortunate  she  is !  "  and  almost  immedi- 
ately, "  But  she  is  only  acting,  how  well  she  plays  her  part ! 
— In  other  words,  we  imagine  her  as  heartbroken,  and  a  mo- 
ment after  as  calm ;  the  two  representations  contradict  one 
another,  and,  as  the  second  is  fortified  with  more  supports, 
more  closely  connected  with  the  aggregate  of  our  former  ex- 
perience, and  backed  up  by  the  body  of  all  our  general  judg- 
ments, the  first  is  negatived,  altered  and  repressed  till  the 
moment  when  the  incidents  and  recollections  which  support 


*  Stendhal,  "  Racine  and  Shakspeare." 


CHAP.  II.]  OF  RECTIFICATION.  229 

its  rival  disappear  with  its  rival,  and  permit  it  again  to  assume 
a  momentary  ascendancy. 

Let  us  now  take  the  second  and  less  familiar  instance. 
We  plunge  halfway  into  water  a  straight  hard  stick,  and  it 
appears  to  be  crooked.  It  is  impossible  for  it  not  to  appear 
so  to  us ;  the  laws  of  optics  and  vision  compel  us  so  to  see  it. 
But  we  recollect  that  the  water  is  soft  and  could  not  bend 
the  wood,  and  that  in  twenty  other  instances,  other  sticks 
plunged  halfway  into  water  have  undergone  the  same  altera- 
tion of  appearance.  We  conclude  that  in  this  instance  also 
the  curvature  is  but  apparent ;  we  assure  ourselves  of  this 
by  drawing  out  the  stick  and  rinding  it  still  straight.  Here 
is  a  rectification ;  in  what  does  it  consist  ? — Even  after  our 
correction,  if  the  stick  be  again  plunged  halfway  into  water, 
we  shall  still  see  it  crooked.  In  other  words,  to  our  visual 
sensation  is  joined'an  associated  perception — that  of  distance 
and  form.  In  other  words,  again,  we  imagine  the  special 
tactile  sensation  which  corresponds  in  general  to  this  visual 
sensation,  and  which  would  be  given  us  by  a  really  crooked 
stick.  In  this  respect  our  associated  perception  is  mislead- 
ing.— But,  by  means  of  former  experiments  we  have  made, 
and  of  the  general  laws  we  are  acquainted  with,  we  pro- 
nounce it  misleading,  and  represent  the  stick  as  straight ; 
in  other  words,  we  imagine  a  different  tactile  sensation,  that 
which  would  be  given  us  by  a  stick  'really  straight.  In  this 
way  we  couple  to  the  first  image  a  second  contradictory 
image,  and  the  first  is  at  once  negatived.' 

So  is  it  with  the  person  who  refers  feelings  of  tingling 
to  a  leg  he  has  lost,  and  so,  again,  with  the  person  subject 
to  hallucination  but  sane,  who,  like  Nicolai,  or  the  patient 
mentioned  by  Bonnet,  sees  figures  of  persons  passing  through 
his  room.  Such  a  patient  has  proved,  by  the  test  of  the 
other  senses,  that  these  figures  correspond  to  nothing  solid. 
He  bases  his  rectification  on  the  testimony  of  all  persons 
present,  and  on  the  accordance  of  all  natural  probabilities. 
He  knows  that  in  the  place  where  he  sees  a  human  figure 
there  is  nothing  more  than  a  wall  hung  with  green  paper. 
In  other  words,  the  image  of  the  wall  so  hung  with  green 
paper  comes  in  conflict  with  the  sensation  of  a  human  figure 


230  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

in  apparently  the  same  place ;  and  the  image,  by  simply 
coupling  itself  with  the  sensation,  negatives  the  sensation. 
This  is  why  the  sick  man  preserves  his  reason,  why  he  re- 
frains from  addressing  the  phantoms,  why  he  seats  himself 
on  the  chair  in  which  they  appear  seated,  in  short,  why  he 
knows  that  he  is  ill,  just  as  the  person  who  has  lost  a  limb 
.knows  he  has  lost  it,  and  does  not  attempt  to  rub  the  absent 
foot  in  which  he  appears  to  feel  the  tingling.  Such  is  the 
power  of  the  contradictory  image ;  it  forms  a  couple  with  the 
contradicted  sensation,  and,  while  this  coupling  lasts,  the 
persisting  contradiction  checks  the  hallucination,  if  not  at 
its  first  stage,  at  all  events  at  its  second. 

III.  Here  a  distinction  must  be  drawn  :  for  the  contra- 
dicted representation  may  have  several  degrees,  from  ex- 
treme dulness  and  feebleness  up  to  complete  energy  and 
precision,  and,  further  still,  up  to  the  abnormal  exaggeration 
which  transforms  it  into  sensation. — In  the  normal  state, 
while  we  are  awake,  our  images  remain  more  or  less  vague 
and  colorless  ;  even  in  intense  reverie,  the  figures  we  imagine, 
the  tunes  we  hum  mentally,  have  not  the  clearness  of  the 
figures  we  see  with  our  open  eyes,  or  of  the  tunes  which  reach 
our  ears  from  a  musical  instrument ;  the  image  of  a  visual  01 
auditory  sensation  is  but  the  feeble  echo  of  that  sensation. — 
But  in  illness  the  image  becomes  exaggerated  till  it  trans- 
forms itself  into  a  complete  sensation.  All  the  hallucinations 
termed*  psycho-sensorial  are  of  this  kind ;  the  evidence  of 
sane  persons  suffering  from  hallucinations,  and  the  actions  of 
insane  persons  so  suffering,  agree  as  to  this. — To  the  same  class 
belong  the  hallucinations  which  precede  sleep  and  of  which 
dreams  are  composed  ;  any  one  of  us  may  observe  in  his 
own  case  the  spontaneous  transformation  by  which,  as  sleep 
gains  upon  us  confused  and  dull  images  become  vivid  and 
precise,  and  acquire  all  the  energy,  relief,  and  detail  of  sen- 
sations. The  numerous  examples  cited  above,  have,  I  think, 
put  this  truth  out  of  reach  of  doubt,  and  the  transformation 
has  been  seen  to  effect  itself  in  two  ways,  sometimes  by  a 
slow  progress  of  which  several  phases  may  be  followed — as  is 


*  Baillarger,  op.  cit. ;  Maury,  op.  cit. 


CHAP.  II.]  OF  RECTIFICATION.  231 

the  case  with  the  reverie  resulting  in  sleep  ;  sometimes  sud- 
denly, after  an  obscure  incubation,  traces  of  which  may  fre- 
quently be  discerned — as  usually  happens  in  cases  of  hallu- 
cination.* 

After  what  has  been  said  of  the  centres  of  sensation  and 
the  cerebral  lobes,  the  physiological  theory  of  this  meta- 
morphosis is  self-apparent.  In  whatever  way  the  sensation 
arises,  it  has  as  its  condition  the  action  of  the  centres  of 
sensation.  In  ordinary  cases  this  action  is  produced  by 
the  disturbance  of  the  nerves.  But,  if  otherwise  produced, 
it  will  arise  without  the  medium  of  the  nerves,  and  we  shall 
have  a  true  sensation,  that  of  a  green  table,  that  of  the  tones 
of  a  violin,  without  any  table  or  any  violin  having  acted  on 
our  eyes  or  ears.  Now,  setting  aside  the  medium  of  the 
nerves,  we  find  two  cases  in  which  the  centres  of  sensation 
come  into  play. — Sometimes,  when  they  have  been  set  in 
action  by  the  nerve  they  spontaneously  persist  in  this  action, 
and  repeat  it  of  themselves  several  times  after  the  nerve  has 
ceased  to  act ;  this  being  notably  the  case  with  the  halluci- 
nations following  the  prolonged  use  of  the  microscope,  when 
the  micrographist,  resting  his  eyes  on  his  table  or  paper,  sees 
a  few  inches  in  front  of  him  small  gray  figures  which  persist, 
become  effaced  and  revive  again,  some  four  or  five  times, 
continually  growing  paler  and  feebler. — Sometimes  the  cen- 
tres of  sensation  come  into  play  by  a  reflected  shock  when 
images,  strictly  so  called,  excite  them  to  action.  Usually,  it 
is  the  sensation  which  excites  the  image,  and  it  is  the  trans- 
mitted action  of  the  centres  of  sensation  which  is  repeated 
in  the  cerebral  lobes  or  hemispheres:  here,  on  the  contrary, 
it  is  the  transmitted  action  of  the  hemispheres  which  is  re- 
peated in  the  centres  of  sensation,  and  the  image  which  ex- 
cites the  sensation.  This  is  probably  the  case  in  hypnogogic 
and  psycho-sensorial  hallucinations. 

If  I  may  be  permitted  a  homely  illustration — let  us  con- 
ceive a  bell-rope,  the  nerve,  a  simple  conductor,  attached  * :/ 
a  large  bell,  the  centre  of  sensation  ;  when  the  rope  is  pulled 


*  See  Part  I.  book  ii.  chap.  I.     Especially  the  story  of  the  gendarme  S.,  p.  67, 
ante. 


232  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BooK  I. 

it  causes  the  bell  to  toll ;  here  we  have  the  sensation.  This 
bell,  thanks  to  an  imperfectly  understood  mechanism,*  com- 
municates by  different  threads,  the  fibres  of  the  optic  thalami 
and  the  corpora  striata,  with  a  system  of  little  bells  which 
make  up  the  hemispheres,  and  whose  mutually  excitable  ring- 
ings exactly  repeat  its  sounds  with  their  pitch  and  tone  ;  these 
ringings  are  images.  When  the  bell  tolls  it  sets  in  motion 
the  ringings,  and  when  the  tolling  is  over  the  ringings  con- 

-  O          O      *  O  O  O 

tinue,  grow  weaker,  and  are  obliterated,  but  are  capable  of 
resuming  and  regaining  all  their  primitive,  energy,  when  a 
favorable  circumstance  permits  the  persisting  sound  of  one 
or  two  of  the  little  bells  to  cause  all  the  rest  to  ring  in  unison. 
—Usually,  the  large  bell  is  set  in  motion  by  the  rope.  But 
sometimes,  when  the  rope  has  ceased  to  pull,  the  bell  contin- 
ues to  toll.  Sometimes  again  it  recommences  to  toll  of  its 
own  accord.  Lastly,  sometimes,  the  little  bells,  which,  as  a 
general  rule,  receive  their  motion  from  it,  transmit  their  mo- 
tion to  it ;  and  we  know  the  principal  conditions  of  these' 
singular  effects. — In  hallucinations  of  the  microscope  the  large 
bell  has  been  so  powerfully  and  constantly  set  vibrating  in 
one  direction,  that  its  mechanism  continues  to  act  even  when 
the  cord  is  motionless. — In  dreams  and  hypnogogic  halluci- 
nations, the  string  is  relaxed ;  it  no  longer  communicates ; 
the  long  employment  of  the  waking  hours  has  rendered  it 
unfit  for  use ;  external  objects  may  pull,  but  it  no  longer 
causes  the  bell  to  toll ;  on  the  other  hand,  at  this  moment, 
the  little  bells  whose  vibrations  have  been  constantly  repress- 
ed while  we  were  awake,  and  whose  pullings  have  been  an- 
nulled by  the  more  powerful  pulling  of  the  bell-rope,  regain 
all  their  power,  they  ring  more  strongly  and  pull  effectu- 
ally; their  disturbance  excites  a  corresponding  disturbance 
in  the  large  bell,  and  the  life  of  man  is  thus  found  to  be  di- 
vided- into  two  portions,  the  waking  state,  in  which  the  large 
bell  rings  by  means  of  the  cord,  and  sleep,  in  which  it  rings 
by  means  of  Jthe  little  bells. — In  abnormal  hallucination 
the  cord  still  pulls,  but  its  effort  is  overcome  by  the  greater 


*  The  anatomical  difficulties  are  too  great. — See,  however,  the  great  work  of 
Lhuys,  "  Recherches  sur  le  Systeme  Nerveux,"  with  plates. 


CHAP.  II.]  OF  RECTIFICATION.  233 

power  of  the  little  bells;  and  various  causes — a  flow  of 
blood,  inflammation  of  the  brain,  haschich — all  the  circum- 
stances capable  of  rendering  the  hemispheres  more  active — 
produce  this  mischance  ;  the  vibrations  of  the  little  bells,  which 
in  the  normal  state  are  more  feeble  than  the  action  of  the 
cord,  have  become  stronger,  and  the  ordinary  equilibrium  of 
the  functions  is  upset,  from  one  of  them  having  assumed  an 
ascendancy  to  which  it  is  not  entitled. 

IV.  Having  settled  this,  we  see  what  may  be  the  effect 
of  the  contradictory  image  and  sensation  on  images  so  ex- 
aggerated.    In  order  that  the  contradictory  sensation  may 
arise  and  negative  them,  it  is  necessary  for  the  images  to  lose 
their  exaggeration,  to  cease  to  excite  sensations,  and  to  return 
to  the  state  of  simple  images ;  in  other  words,  the  little  bells 
must  cease  to  set  the   great  bell    tolling.     Such  is  the  case 
when  we  wake  up ;  just  now,  in  a  dream,  I  imagined  myself 
to  be  in  a  burning  atmosphere ;  I  wake  up  and  have  the  sen- 
sation of  ordinary  temperate  warmth ;  this  sensation  of  com- 
parative cold  contradicted  the  image  of  the  sensation  of  heat, 
and,  by  means   of  this  coupling,  the  image  appeared  in  its 
actual  state,  that  is,  as  a  simple  image. — But  if,  through  any 
derangement,  the  little  bells   continue  to  set  the  great  bell 
tolling,  which  is  what  happens  with  the  sufferer  from  hallu- 
cination who   perceives  an   absent  person,  if  the  great  bell 
repeats  its  tolling  of  its  own  accord,  which  is  what  happens  in 
the  hallucinations  following  the  prolonged  use  of  the  micros- 
cope, the  result  is  different.     The  patient  may  know  the  phys- 
iological cause  of  the  error,  may  base  his  reasoning  on  the 
evidence  of  surrounding  persons,  may  prove  by  the  aid  of  the 
other  senses  that  the  phantom  is  but  a  phantom,  still  he  con- 
tinues  to   see  it.     In  Nicolai's   case   the   figures   continued 
to  pass  through  his  room,  and  the  little  gray  specks  persist 
in  appearing  on  the  blank  paper  placed  before  the  micrograph- 
ist. — In   fact,  the  contradictory   sensation  is  no   longer  pro- 
duced.    The  paper  ceases  to  give  the  sensation  of  white  at 
the  place  in  which  it  appears  to  be  covered  with  gray  patches, 
and  the  green  or  brown  wall  of  the  room  ceases  to  give  the 
sensation  of  green  or  brown  in  the  places  at  which  the  figures 
come  in  the  way.     The  optic  nerve  is  impressed  by  the  white 


234  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

rays  of  the  paper  or  the  green  and  brown  rays  of  the  wall, 
but  ineffectually  so  ;  its  action  is  no  longer  communicated  to 
the  centre  of  sensation.  The  place  is  occupied ;  another  ac- 
tion is  set  up  and  persists  there,  resisting  all  the  solicitations 
of  the  nerve. 

There  remains,  then,  a  single  corrective,  the  image  strictly 
so  called,  the  image  of  the  green  or  brown  wall  which  Nicolai 
attempted  to  picture  to  himself  in  the  place  of  the  phantoms, 
the  image  of  the  plain  white  paper  which  the  micrographist 
represents  to  himself  in  the  place  of  his  paper  spotted  with 
gray  outlines.  But  this  image  remains  a  simple  image;  it 
does  not  become  exaggerated  to  the  extent  of  setting  in  mo- 
tion the  centre  of  sensation  and  transforming  itself  into  a  sen- 
sation. Nicolai  observed  a  very  marked  difference  between 
the  figure  of  a  person  as  it  appeared  to  him,  and  the  same 
figure  as  he  pictured  it  a  moment  after  by  an  effort  of  atten- 
tion and  memory.  The  first  invariably  seemed  an  external 
thing,  the  second  an  internal,  a  simple  mental  representation ; 
in  fact,  in  the  first  case,  the  centre  of  sensation  was  operating, 
and,  in  the  second,  it  did  not  operate. — Hence  it  follows  that 
the  correction  afforded  by  the  contradictory  image  is  limited. 
The  person  under  hallucination,  even  when  sane,  continues 
to  see  his  phantoms  as  external ;  in  fact,  in  his  case,  the  cen- 
tres of  sensation  operate  precisely  as  if  he  had  before  his  eyes 
real  persons.  Although  the  bell-rope  does  not  pull,  the  large 
bell  tolls  as  usual ;  the  little  bells  of  the  hemispheres  are  pow- 
erless ;  the  contradictory  image  can  do  nothing  against  the 
sensation  itself.  It  has  no  effect  except  upon  the  consequence 
of  the  hallucinations  so  produced.  If  it  were  wanting,  these 
consequences  would  be  madness  ;  the  patient  would  imagine 
and  reason  about  his  phantoms,  as  he  imagines  and  reasons 
about  external  objects :  the  micrographist  would  try  to  rub 
out  the  gray  patches  on  his  paper,  Nicolai  would  have  spoken 
to  the  imaginary  friends  who  came  to  visit  him,  and  have 
asked  them  how  they  were. — Here  it  is  that  the  contradictory 
image,  supported  by  the  whole  troop  of  general  convictions, 
intervenes  with  success.  Against  sensations,  that  is  to  say 
against  a  state  of  the  sensory  centres  on  which  it  has  no  hold, 
it  was  powerless.  Against  ideas,  representations,  and  reason- 


CHAP.  II.]  OF  RECTIFICATION.  23$ 

ings,  all  founded  on  images  resembling  it,  and  situated  like  it 
in  the  hemispheres,  it  is  effective.  Rectification,  of  no  effect 
in  the  first  stage,  becomes  sufficient  in  the  second. 

V.  Let  us  now  study  the  contradicted  image,  as  it  remains 
in  the  normal  state  of  wakefulness,  that  is  to  say  when  it  does 
not  set  in  motion  the  centres  of  sensation,  and  does  not  be- 
come exaggerated  to  the  extent  of  being  transformed  into  a 
sensation. — In  this  state  it  constitutes,  in  the  first  placeman 
event  of  capital  importance  which  we  term  recollection. 

Let  the  reader  recall  some  recollection  of  his  own,  and 
abandon  himself  to  it,  especially  if  it  be  recent,  vivid,  and 
prolonged  ;  he  will  thus  obtain  a  better  insight  into  its  nature. 
A  month  ago  I  spent  three  hours  on  the  pier  at  Ostend,  en- 
gaged in  watching  the  sun  which  was  setting  in  a  clear  sky,  and 
at  this  present  moment  I  recall  without  difficulty  the  level 
street,  the  dyke  paved  with  reddish  bricks,  the  vast  extent  of 
glittering  water,  all  the  incidents  of  my  walk,  the  sailor,  and 
the  two  loungers  I  spoke  to,  my  long  reverie  at  the  pier-head, 
from  whence  I  watched  the  declining  day,  and  the  variations 
of  the  moving  sea,  the  luminous  twinkling  of  the  waves,  their 
bluish  hollows  striped  with  russet  tints,  all  the  splendor  of  the 
vast  watery  carpet,  undulating  and  displaying  itself  with  its 
changing  colors,  like  a  silk  of  Jordaens. — These  are  images, 
that  is  to  say  spontaneous  revivals  of  anterior  sensations,  and, 
like  all  images,  they  admit  of  an  illusion  when  they  become 
intense  and  clear.  In  fact,  there  are  moments  when  we  be- 
lieve for  a  half-second  that  we  see  real  objects ;  I  experienced 
this  just  now,  and  artists,  writers,  all  who  have  precise  and 
lucid  memories,  are  well  aware  of  this;  a  nervous  person  who 
has  undergone  a  surgical  operation,  or  met  with  some  serious 
accident,  bears  the  same  testimony  ;*  the  keenness  of  the  rec- 
ollection is  so  great  that  he  will  sometimes  grow  pale  and  utter 
a  cry.  In  this  state  we  forget  ourselves,  we  lose  conscious- 
ness of  the  present ;  we  feel,  before  the  internal  phantasmago- 
ria, as  we  do  at  the  theatre  when  a  good  piece  is  being  played. 
We  become  for  the  moment  dupes  of  the  half-dream,  then 
cease  to  be  so,  then  again  become  so,  then  again  cease  to  be 


*  See  Part  I.  book  ii.  chap,  i,  p.  42. 


236  GENERAL  MECHANISM  OF  KNOWLEDGE.       [KooK  I. 

so :  thus  an  incessantly  interrupted  series  is  formed  of  beliefs 
incessantly  denied,  and  of  illusions  incessantly  set  right. — But 
here  the  denial  and  the  correction  result  in  a  new  and  mar- 
vellous effect,  whose  mechanism  is  so  simple  that  we  neglect 
to  observe  it,  one  of  infinite  extent,  and  which,  by  its  adjust- 
ment to  things,  constitutes  memory.  At  present,  by  virtue  of 
this  correction,  the  present  image  appears  tome  as  a  past  sen- 
sation ;  this,  strictly  speaking,  is  recollection. — No  doubt,  a 
moment  afterwards,  on  reflection,  I  shall  know  that  all  there 
is  in  my  mind  is  a  present  image,  that  this  vivid  internal  half- 
sight  of  blue  waves  spangled  with  gold  and  set  in  a  semicircle 
of  white  sand,  is  entirely  present  and  internal.  But  this  will 
be  an  ulterior  and  supplementary  correction,  a  rectification 
upon  a  rectification,  a  second  and  last  stage  in  the  series  of 
reductions  through  which  the  image  passes  in  order  finally  to 
appear  as  it  actually  is. — At  the  first  stage,  at  the  moment  at 
which  we  are,  it  still  appears  as  a  sensation,  not  as  a  present 
sensation,  as  happens  in  hallucination  proper  and  dreams,  but 
as  a  past  sensation  situated  at  a  greater  or  less  distance  from 
the  present  moment,  as  the  sensation  of  certain  glittering 
blue  and  certain  dead  white,  placed  in  between  my  present 
sensations  and  other  still  more  distant  ones. — And  in  fact, 
when  a  lengthy  series  of  well-connected  sensations  arises 
within  us,  when  we  mentally  live  over  the  incidents  of  a  day's 
travel,  we  believe  ourselves  to  be  confronted  with  real,  though 
distant  facts.  The  images  of  sounds,  colors,  pains,  pleasures, 
which  are  nothing  more  than  present  images,  but  which  cor- 
respond to  anterior  sensations,  seem,  as  they  pass  in  review 
before  us,  our  anterior  sensations  themselves.  All  there  is 
within  us  is  the  present  echo  of  a  distant  impression  ;  never- 
theless, what  we  affirm  is  not  the  echo,  it  is  the  distant  im- 
pression, and  by  an  admirable  correspondence  we  affirm  it 
truthfully. 

Such  is  the  crude  fact,  and  we  see  that  recollection,  like 
external  perception,  is  a  true  hallucination,  that  is  to  say, 
an  illusion  which  results  in  a  cognition.  It  is  an  illusion,  since 
the  present  image  which  constitutes  it  is  taken,  not  for  a 
present  image,  but  for  a  past  sensation,  thus  appearing  other 
than  it  really  is.  It  is  a  cognition,  since  in  the  past,  and 


CHAP.  II.]  OF  RECTIFICA  TION.  237 

precisely  at  the  proper  place  there,  a  sensation  is  met  with 
exactly  similar  to  the  affirmed  sensation,  and  our  judgment, 
which  is,  in  itself  and  directly,  false,  is  thus  found,  indirectly 
and  by  coincidence,  to  be  true. — Here  again  nature  deceives 
to  instruct  us.  Just  as  in  external  perception  we  have  seen 
simple  internal  phantoms  taken  for  external  objects,  but  by 
an  admirable  adaptation  corresponding  to  the  presence  of 
real  external  objects,  so  in  memory  we  see  simple  present 
images  taken  for  past  sensations,  but  corresponding,  by  as 
beautiful  a  mechanism,  to  the  anterior  presence  of  real  sen- 
sations.— Thus,  the  first  repression  which  the  image  under- 
goes, and  which  checks  the  complete  hallucination  in  which 
the  image  would  naturally  have  resulted,  opens  to  us  a  new 
world,  that  of  time  and  space.  In  this  intermediate  state, 
partially  abortive  and  partially  complete,  half  rectified  and 
half  hallucinatory,  the  image  resembles  some  organ*  checked 
in  the  midst  of  its  development,  a  special  product,  utilised 
for  special  functions,  and  sometimes  for  functions  of  the 
highest  order.  This  is  the  case  here,  since  here  we  owe  to  it 
our  knowledge  of  the  past,  and,  consequently,  our  previsions 
of  the  future. 

Here  again  we  seize  in  the  act  an  illusion  of  conscious- 
ness.— When  a  psychologist  observes  an  act  of  memory,  he 
begins  by  remarking  that  it  is  a  cognition,  and  postulating 
that  every  cognition  implies  two  terms,  a  subject  knowing, 
and  an  object  known,  he  says  that  there  are  two  terms  in- 
volved in  recollection,  the  past  sensation  and  the  knowledge 
we  have  of  it.  If  he  then  goes  on  to  examine  this  knowledge 
he  is  tempted  to  take  it  for  a  simple  naked  act  of  the  mind, 
deprived  of  all  sensible  character,  and  indeed  of  all  character, 
except  its  connection  with  the  past  sensation  which  is  its 
object.  He  is  consequently  disposed  to  regard  this  cognition 
as  a  pure  act  of  attention,  an  act  unique  in  kind,  incapable 
of  comparison  with  any  other,  whose  essence,  purely  spiritual, 
consists  solely  in  putting  us  in  communication  with  our  past 
life. — But  if  this  act  appears  to  be  pure  and  spiritual,  it  is 


*  As,  for  instance,  the  stamens  and  other  parts  of  a  flower,  which  are  petals 
checked  in  the  course  of  their  development. 


238  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

because  it  is  empty;  he  has  himself  emptied  it  by  taking 
from  it  all  its  characters,  to  set  them  apart  and  form  from 
them  the  object.  In  fact,  that  which  constitutes  recollection 
or  act  of  memory  is  the  present  image  which  a  past  sensa- 
tion has  left  in  us,  an  image  which  we  find  affected  with  an 
apparent  recoil,  and  which  seems  to  us  the  sensation  itself, 
By  cutting  away  from  the  image  all  that  constitutes  it,  and 
all  the  positive  properties  by  which  it  resembles  the  sensa- 
tion, and  referring  them  to  the  sensation  itself,  we  turn  recol- 
lection from  a  full  act  into  an  abstract  one ;  as  this  act  no 
longer  comprises  any  thing,  nothing  can  be  said  about  it ;  we 
name  it,  and  there  is  science  completed.  Here,  as  with  ex- 
ternal perception,  we  have  made  the  mistake  of  splitting  in 
two  our  internal  act,  and  here,  as  with  external  perception, 
we  are  led  to  do  this  from  its  having  two  aspects.  On  the 
one  hand,  as  it  passes  within  us,  and  at  the  present  moment, 
it  is  our  present  act ;  on  the  other  hand,  as  it  is  hallucinatory, 
it  seems  to  us,  in  external  perception,  an  object  other  than 
ourselves,  and,  in  recollection,  a  sensation  not  actually  present. 
It  was  necessary  to  recognize  its  hallucinatory  nature  to  un- 
derstand that  it  is  single,  and  that  while  in  reality  internal  and 
present,  it  is  in  appearance  only  that  it  is  an  external  thing, 
or  past  event.  Until  this  remark  is  made,  we  divide  it  into 
an  internal  act  and  known  object.  In  this  operation  the  act 
loses  all  that  the  object  gains  ;  a  transfusion  of  characters  is 
effected  to  the  detriment  of  the  first  and  to  the  advantage  of 
the  second.  Thereupon  consciousness,  self-deceived,  declares 
that  in  recollection,  as  in  external  perception,  the  mind  per- 
forms an  act  sui  generis,  simple,  irreducible  to  any  other, 
mysterious,  marvellous,  ineffable ;  and  thus  a  new  thread  is 
added  to  the  constantly  broken  and  constantly  repaired  cob- 
web, in  which  the  moral  sciences  have  been  entangling  them- 
selves for  so  many  ages. 

VI.  Let  us  now  examine  more  closely  the  apparent  recoil 
which  the  image  undergoes.  I  am  quietly  stretched  in  the 
shade  of  a  hedge,  listening  to  the  chirpings  of  the  birds,  and 
the  prolonged  buzzing  of  the  insects  flitting  about  in  the 
summer  air ;  suddenly  a  distant  rolling  is  heard ;  it  increases, 
and  comes  on  me  with  a  furious  grinding  and  growling  noise 


CHAP.  II.]  OF  RECTIFICA  TION.  239 

like  a  peal  of  thunder ;  I  jump  up,  a  railway  train  is  passing ; 
I  had  been,  without  knowing  it,  within  ten  paces  of  the  line. 
The  hoarse  roll  grows  weaker  and  becomes  effaced  ;  listen  as 
I  may,  I  hear  nothing  but  the  indistinct  murmur  of  the 
country  and  the  monotonous  rustling  of  leaves  shaken  by 
the  wind.  But  in  this  silence  the  image  of  the  resounding 
noise  persists,  disappears,  and  reappears,  till  some  other  pre- 
occupation or  some  other  vivid  emotion  drives  it  from  the 
stage  to  make  way  for  a  new  actor. — Now,  at  each  of  its  re- 
entries, the  image  finds  itself  in  conflict  with  the  then  present 
group  of  sensations.  If,  in  conformity  to  its  natural  ten- 
dency, it  appeared  as  a  sensation,  there  would  be  a  contra- 
diction between  it  and  this  group.  In  fact,  I  cannot  repre- 
sent myself  as  at  the  same  time  tranquil,  reclining,  listening 
to  the  vague  little  sounds,  and  as  startled,  springing  up, 
deafened  by  a  violent  noise  ;  the  first  representation  is  in- 
compatible with  the  second ;  in  ordinary  language,  the  one 
negatives  the  other.  But  this  negation  is  on  one  point  only ; 
the  one  negatives  the  other  only  as  being  its  contemporary. 
The  ordinary  hallucinatory  process  is  checked  in  this  point 
only,  since  a  negation  on  this  point  only  is  sufficient  to  enable 
both  to  subsist :  there  is  a  minimum  of  repression  propor- 
tioned to  a  minimum  of  antagonism.  Consequently,  in  other 
respects,  the  hallucinatory  process  takes  effect ;  the  image, 
not  being  negatived  as  a  sensation,  but  as  a  present  sensa- 
tion, appears  as  a  sensation  which  is  not  present,  and  the  only 
result  of  the  negation  it  undergoes  is  to  reject  it,  as  far  as 
appearance  goes,  out  of  the  present. 

Why  is  this  rejection  a  recoil?  And  why  does  the  appar- 
ent sensation  seem  to  take  a  backward  rather  than  a  forward 
direction  ? — It  must  be  observed  that  every  image,  much 
more,  then,  every  series  of  images,  has  a  certain  duration  ;  for 
every  image  repeats  a  sensation,  and  we  have  seen  that  the 
shortest  sensations,  even  those  we  consider  instantaneous,  are 
series  of  elementary  sensations,  themselves  composed  of  still 
more  elementary  ones.  Hence  it  follows  that  every  image 
occupies  a  portion  of  time,  and  has  two  extremities — an  ante- 
rior one  joining  on  to  preceding  events,  and  a  posterior  one 
joining  on  to  subsequent  events:  the  first  one  attached  to 


240  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

the  past,  the  second  attached  to  the  future.  And  thus,  a 
simple  sound,  a  color  perceived  by  a  momentary  glance,  a 
brief  sensation  of  heat,  smell,  or  contact,  whose  successive 
parts  we  do  not  distinguish,  is  similar  in  nature  to  a  drive  or 
walk  whose  successive  parts  we  do  distinguish,  and  every  sen- 
sation, consequently  every  image,  possesses,  like  every  series 
of  sensations  or  imag-es,  its  beginning  and  its  end.  Thus, 
when  hearing  a  note  on  the  piano  I  recall  the  preceding  note, 
the  case  is  similar  to  that  in  which,  when  thinking  over  the 
events  of  the  day,  I  recall  the  events  of  yesterday.  When  the 
present  sensation  and  the  image  of  the  preceding  sensation 
come  into  conflict  they  have  each  two  extremities ;  neither 
one  nor  the  other  are  instantaneous  and  simple  ;  they  are 
two  wholes  composed  of  successive  elements.  This  is  why 
the  repulsion  by  which  the  first  acts  on  the  second  is  itself 
an  aggregate  of  repulsions— repulsions  which  are  unequal, 
and  which,  by  their  distribution,  determine  the  direction  in 
which  the  apparent  rejection  takes  place. 

Let  us  first  consider  the  two  extremities  of  the  sensation, 
or  of  the  present,  in  their  relation  with  the  posterior  extrem- 
ity of  the  image,  or  of  the  past.  The  posterior  extremity  of 
the  past  coincides  with  the  anterior  extremity  of  the  present ; 
here  then  the  contradiction,  and  consequently  the  repulsion, 
has  no  effect.  But  it  is  at  the  greatest  possible  distance  from 
the  posterior  extremity  of  the  present ;  here  then  the  -con- 
tradiction, and  consequently  the  repulsion,  is  at  its  maximum. 
Hence  we  see  that  the  rejection  must  take  place  in  a 
backward  direction,  so  that  under  the  pressure  of  the 
present  sensation  the  posterior  extremity  of  the  image 
seems  to  coincide  with  the  anterior  extremity  of  the  present 
sensation,  and  to  separate  itself  as  far  as  it  can  from  the  pos- 
terior extremity  of  the  present  sensation. — Let  us  now  con- 
sider the  two  extremities  of  the  past  in  their  relation  with 
the  anterior  extremity  of  the  present.  The  anterior  extrem- 
ity of  the  present  coincides  with  the  posterior  extremity  of 
the  past ;  here  then  the  contradiction,  and  consequently  the 
repulsion,  is  of  no  effect.  But  it  is  at  the  greatest  possible 
distance  from  the  anterior  extremity  of  the  past ;  here  then 
the  contradiction,  and  consequently  the  repulsion,  is  at  its 


CHAP.  II.]  OF  RECTIFICA  TION.  241 

maximum.  Hence  we  see  that,  in  the  whole  rejection  into  the 
past,  the  anterior  extremity  of  the  sensation  must  apparently 
coincide  with  the  posterior  extremity  of  the  image,  and  ap- 
pear at  the  greatest  possible  distance  from  the  anterior  ex- 
tremity of  the  image. — In  cases  of  prevision,  the  inverse  takes 
place.  According  as  the  relation  of  the  extremities  of  the 
image  with  the  extremities  of  the  actual  sensation  is  different, 
the  balance  inclines  in  one  direction  or  the  other,  and  we  may 
at  any  moment  witness  in  our  own  cases  these  remarkable 
changes  of  place. 

I  meet  casually  in  the  street  a  person  whose  appearance  I 
am  acquainted  with,  and  say  to  myself  at  once  that  I  have 
seen  him  before.  Instantly  the  figure  recedes  into  the  past, 
and  there  wavers  about  vaguely  without  at  once  fixing  itself 
in  any  spot.  It  persists  in  me  for  some  time,  and  surrounds 
itself  with  new  details.  "  When  I  saw  him  he  was  bare-headed, 
with  a-working  jacket  on,  painting  in  a  studio  ;  he  is  so-and-so, 
of  such-and-such  a  street.  But  when  was  it  ?  It  was  not 
yesterday,  nor  this  week,  nor  recently.  I  have  it ;  he  told  me 
that  he  was  waiting  for  the  first  leaves  to  come  out  to  go  into 
the  country.  It  was  before  the  spring.  But  at  what  exact 
date  ?  I  saw,  the  same  day,  people  carrying  branches  in  the 
streets  and  omnibuses  :  it  was  Palm  Sunday  !  " — Observe  the 
travels  of  the  internal  figure,  its  various  shiftings  to  front  and 
rear  along  the  line  of  the  past ;  each  of  these  mental  senten- 
ces has  been  a  swing  of  the  balance.  When  confronted  with 
the  present  sensation,  and  with  the  latent  swarm  of  indistinct 
images  which  repeat  our  recent  life,  the  figure  has  first  re- 
coiled suddenly  to  an  indeterminate  distance.  Then,  completed 
by  precise  details,  and  confronted  with  all  the  shortened  images 
by  which  we  sum  up  the  proceedings  of  a  day  or  a  week,  it  has 
again  receded  beyond  the  present  day,  beyond  yesterday,  the 
day  before,  the  week,  still  further,  beyond  the  ill-defined  mass 
constituted  by  our  recent  recollections.  Then  something  said 
by  the  painter  was  recalled,  and  it  at  once  receded  again  be- 
yond an  almost  precise  limit,  which  is  marked  by  the  image  of 
the  green  leaves  and  denoted  by  the  word  spring.  A  mo- 
ment afterwards,  thanks  to  a  new  detail,  the  recollection  of 
the  branches,  it  has  shifted  again,  but  forward  this  time,  not 
16 


242  GENERAL  MECHANISM  OF  KNOWLEDGE.        [BOOK  I. 

backward  ;  and,  by  a  reference  to  the  calendar,  is  situated  at 
a  precise  point,  a  week  further  back  than  Easter,  and  five 
weeks  nearer  than  the  Carnival,  by  the  double  effect  of  the 
contrary  impulsions,  pushing  it,  one  forward  and  one  back- 
ward, and  which  are,  at  a  particular  moment,  annulled  by  one 
another. — Now  let  us  place  this  image  in  an  inverse  situation, 
that  is  to  say  in  such  a  manner  that  its  anterior,  and  no  longer 
its  posterior,  extremity  may  join  on  to  the  posterior  ex- 
tremity of  present  sensations.  At  once,  instead  of  sliding  to- 
wards the  past,  it  slides  towards  the  future.  This  is  what  hap- 
pens if  I  calculate  when  I  shall  see  my  friend  again.  The 
more  this  shifting  is  repeated  at  the  successive  contact  of  the 
previsions  which  the  figure  meets  with  in  its  way,  the  more 
does  it  seem  to  fly  forward  and  to  become  distant.  Finally, 
it  becomes  placed  ;  but  its  precise  place  is  attained  only  by  its- 
projection  being  stopped.  A  new  detail  must  intervene  to 
give  it,  after  successive  movements  in  advance,  a  movement 
backwards,  which  will  fix  and  intercalate  it  between  two  fu- 
ture periods.  "  I  shall  see  my  friend,  not  to-day,  not  to-mor- 
row, but  the  day  after  to-morrow,  not  the  day  after  to-mor- 
row in  the  morning,  but  in  the  afternoon,  when  I  leave  the 
library,  before  I  go  home  to  dinner."— In  this  perpetual  play, 
which  has  ceased  to  attract  our  attention  because  we  live  in 
it,  the  shifting  image  is  actually  contemporary  with  the  sen- 
sation or  image  which  causes  it  to  shift,  but  nevertheless  seems 
to  be  situated  before  or  after  it.  In  fact,  one  over-rides  the 
other ;  in  appearance,  they  are  placed  end  to  end ;  and  this 
marvellous  illusion  which,  out  of  two  really  simultaneous 
events,  forms  two  events  apparently  posterior  or  anterior  to 
one  another,  is  the  mechanism  by  which  our  sight  extends 
out  of  the  present  to  attain  the  past  and  the  future. 

VII.  The  last  state  of  the  image  now  remains  to  be  con- 
sidered, that  state  in  which  it  ceases  to  appear,  not  only  as  an 
actual  sensation,  but  as  a  past  or  future  sensation.  In  this 
case  we  pronounce  it  to  be  a  simple  image,  and  the  rectifica- 
tion is  complete. — Of  this  kind  are  all  the  internal  events  we 
term  pure  conceptions,  pure  imaginations,  and  generally  pure 
ideas.  This  is  what  happens  when  we  read  or  hear  a  sentence, 
when  we  dream  or  form  projects.  We  then  picture  to  our- 


CHAP.  II.]  OF  RECTIFICA  TION.  243 

selves,  more  or  less  clearly  and  with  more  or  less  minuteness 
of  detail,  some  room,  some  landscape,  certain  persons  or  inci- 
dents, and,  as  they  pass  before  our  mental  vision,  we  know 
that  they  are  imaginary,  supposititious,  and  entirely  of  our 
own  fabrication.  In  fact,  if  we  expect  our  perceptions  of  ex- 
ternal objects,  our  recollections  and  our  previsions,  the  whole 
web  of  our  thought,  during  our  waking  hours,  is  made  up  of 
pure  images.  When  I  think  of  an  old  time-piece  in  an  ad- 
joining room,  when,  by  aid  of  mental  words,  I  follow  out  a 
long  train  of  reasoning,  when  I  reflect  on  what  will  probably 
happen  if  I  take  certain  steps,  not  only  have  I  in  my  mind 
the  image  of  the  time-piece,  the  image  of  the  sounds  and  vocal 
movements  which  my  arguments  would  require,  if  uttered 
aloud,  the  image  of  the  gestures,  emotions,  and  events  which 
my  conduct  would  excite  in  myself  and  others,  but  I  am  aware 
too  that  all  these  images  are  simple  present  images.  This 
time  the  hallucination  is  wholly  checked  ;  the  internal  phan- 
tasmagoria, repressed  the  moment  it  arises,  appears  only  as 
phantasmagoria,  and  here  the  mechanism  of  the  repression  is 
easily  detected. 

Two  extreme  cases  present  themselves  and  sum  up  all  the 
rest.  In  the  first,  the  image  is  a  reduced  and  impoverished 
recollection.  We  all  know  that  it  is  in  its  primitive  state 
a  recollection,  and  a  full  and  circumstantial  one.  I  have 
seen  the  time-piece  I  picture  to  myself  a  hundred  times ;  I 
have  heard  or  read  a  thousand  or  ten  thousand  times  the 
mental  words  which  pass  through  my  mind  ;  I  have  observed 
thirty  or  forty  times  the  astonished  gesture,  the  pleased 
smile  or  angry  accent  I  imagine ;  the  proof  is  that  they  re- 
vert to  me  ;  if  I  know  them,  it  is  because  I  recollect  them. 
But  certainly,  when  I  first  observed  them,  I  was  struck  by 
their  accompaniments,  and  shortly  afterwards  I  could  have 
described  their  surroundings  from  memory,  the  fire-place  in 
the  country,  where  the  old  time-piece  stood  when  I  was  a 
child,  the  name  of  the  person  who  made  the  gesture,  the 
title  of  the  book  in  which  I  saw  the  word. — Take,  for  in- 
stance, a  Latin  word,  securis.  No  doubt  on  the  day  I  learnt 
this  word,  I  could  recall  the  grammar  or  dictionary  in  which 
I  read  it,  the  exact  place,  the  line  and  page  of  the  dog's- 


244  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

eared,  blotted  school-book.  But  since  then,  these  circum- 
stances have  disappeared ;  repetition  and  distance  have  ef- 
faced them  ;*  the  image  which  I  then  situated  at  a  particular 
spot  of  my  past  life,  has  lost  the  details  which  situated  it. 
Now  do  what  I  will  in  shifting  it  over  the  whole  line  of  my 
anterior  experience,  it  does  not  attach  itself  to  any  of  the 
successive  links.  It  is  too  much  worn  and  blunted ;  it  has 
no  longer  re-entering  and  salient  angles,  special  and  peculiar 
extremities,  fixing  it  before  or  after  some  other  distinct  recol- 
lection. I  no  longer  find  in  it  an  anterior  or  posterior  ex- 
tremity which  may  blend  and  coincide  with  the  posterior  or  an- 
terior extremity  of  another  determinate  event.  Thus  it  moves 
about,  in  a  colorless  way ;  if  I  detect  its  place  in  the  vague  dis- 
tance of  childhood,  it  is  by  conjecture  and  reasoning;  of  itself, 
it  no  longer  finds  a  place  ;  it  has  no  longer  antecedent  or  con- 
sequent, it  is  deprived  of  situation. — And,  if  we  look  to  the 
future,  its  position  is  the  same,  since  its  future  existence  ap- 
pears subject  to  certain  conditions,  among  others  to  my 
changing  will,  and  since,  in  the  realm  of  the  future,  it  is  still 
colorless,  and  capable  of  intercalating  itself  as  well  at  one 
moment  as  at  another  of  my  future  experience. — On  both 
sides  its  situation  fails  it ;  it  is  essentially  unstable  ;  I  cannot 
fix  it  or  affirm  it ;  thus,  it  is  opposed  to  preceding  affirma- 
tive judgments,  to  previsions,  and  recollections.  This  is 
how  it  happens  that  when,  like  them,  it  undergoes  the 
repression  of  contradictory  sensations  it  is  contradicted, 
not  partially  as  they  are,  but  absolutely,  and  cannot  appear 
other  than  as  a  sensation  without  situation,  that  is,  as 
a  sensation  simply  apparent  and  destitute  of  real  exist- 
ence. 

Such  is  the  first  case ;  let  us  examine  the  second,  which 
is  just  the  inverse.  Here  we  have  the  precise,  intense,  col- 
ored representations  attained  by  the  imaginations  of  great 
artists — Balzac,  Dickens,  Flaubert,  Henri  Heine,  Edgar  Poe ; 
and  some  of  which  I  have  already  cited.  These  artists  attain 
moments  of  hallucination  :  but  it  is  for  the  moment  only. 
M.  Flaubert  writes  to  me  as  to  this :  "  Do  not  assimilate  the 


*  See  part  i.  book  ii.  chap.  2,  "  Laws  of  the  Obliteration  of  Images." 


CHAP.  II.]  OF  RECTIFICA  TION.  24$ 

mental  vision  of  the  artist  with  the  state  of  the  man  laboring 
under  hallucination.  I  know  both  states  perfectly ;  there  is 
a  chasm  between  them.  In  strict  hallucination  there  is  al- 
ways fear ;  you  feel  your  personality  escaping  you  ;  you  think 
you  are  about  to  die.  In  poetic  vision,  on  the  contrary,  there 
is  pleasure  ;  it  is  something  which  enters  into  you.  It  is  none 
the  less  true  that  one  loses  consciousness  of  where  he  is." 
He  adds,  further  on,  "This  vision  frequently  completes  itself 
slowly,  piece  by  piece,  like  the  different  parts  of  a  decoration 
are  put  together ,  "  but  frequently,  also,  it  is  sudden  and  "  fu- 
gitive, like  the  hallucinations  preceding  sleep.  Something 
passes  before  your  eyes ;  you  must  seize  it  on  the  spot,  greed- 
ily."— My  own  experience  is  in  accordance  with  these  re- 
marks. When  the  landscape,  the  moving  figure,  the  gesture 
and  voice  of  the  person  begin  to  rise  and  become  precise,  we 
wait,  and  hold  the  breath ;  sometimes,  then  all  appears  sud- 
denly ;  at  other  times,  slowly,  with  barren  intervals. — But,  in 
both  cases,  what  appears  is  watched  for,  desired,  or  at  least 
comprised  in  the  circle  of  watched-for  and  desired  images, 
then  immediately  employed,  and  put  to  use  by  the  hand 
which  marks  and  notes  it,  consequently  followed  at  once  by 
repressive  sensations,  in  all  cases  stamped  at  its  origin  with  a 
particular  character — the  property  of  springing  up  by  a  per- 
sonal effort,  in  a  foreseen  direction,  after  a  preliminary  search, 
as  an  internal  effect  and  not  as  an  external  impression ;  so 
that  after  such  a  burst  and  dazzling,  the  habitual  sensations, 
tactile,  muscular,  or  visual  have  no  difficulty  in  resuming  their 
normal  ascendancy,  and,  combined  with  the  rank  of  positive 
recollections,  drive  back  the  enfeebled  phantom  into  the  in- 
aginary  world. — A  sequence  of  very  short  hallucinations, 
which,  being  voluntary,  may  be  and  are  actually  broken  and 
negatived  at  any  moment  by  the  more  or  less  vague  percep- 
tion of  the  real  world,  such  is  the  picturesque  or  poetic  vision, 
very  different,  as  M.  Baillarger  observes,  from  strict  hallucin- 
ation, which  rises  unexpectedly,  and  without  the  concurrence 
of  the  will,  which  persists  in  spite  of  ourselves,  which  is  devel- 
oped of  its  own  accord,  irregularly,  and  which  seems  to  us  the 
work  of  some  extrinsic  power. — In  themselves,  the  two  events 
are  similar.  But  they  are  contrasted  in  their  antecedents  and 


246  GENERAL  MECHANISM  OF  KNOWLEDGE.      [BOOK  I. 

consequents  ;  the  first  is  the  harmonious  product  of  all  the 
united  tendencies  of  the  human  being ;  the  second,  the 
exaggerated  enlargement  of  a  discordant  element,  which, 
like  an  organ  become  hypertrophied  and  subtracted  from 
general  life,  is  developed  separately  and  abnormally  to  the 
detriment  of  the  others  with  whose  concordant  action  it 
interferes. 

We  see  now  how  it  is  that  our  ordinary  conceptions  and 
imaginations  appear  to  us  as  such,  and  do  not  create  illusion  ; 
they  are  all  comprised  between  two  extreme  states,  and  each 
of  these  two  states  includes  a  peculiarity  repressing  the  illu- 
sion.— Either,  as  in  the  ordinary  case,  they  are  vague  and  strip- 
ped of  precise  details,  in  such  a  way  that,  cast  out  of  the  pres- 
ent by  the  contradiction  of  present  sensations,  they  are  want- 
ing in  angles  which  may  fix  them  in  the  past  and  future ; 
whence  it  follows  that,  being  deprived  of  all  situation  in  time, 
they  appear  excluded  from  time,  that  is  to  say  from  real  life, 
and  are  pronounced  apparent,  false,  and  purely  imaginary  sen- 
sations.— Or,  after  a  series  of  repeated  solicitations,  they  at- 
tain the  detail  and  precision  of  the  real  sensation,  by  suspend- 
ing contemporary  sensations  and  ordinary  recollections,  but 
for  the  moment  only,  by  a  fugitive  ecstasy,  interrupted  an  in- 
stant after  by  a  return  to  the  normal  state,  and  then  pro- 
nounced illusory  or  internal,  because  the  effort  of  internal  will 
of  which  it  is  the  result  re-arises  with  it  in  the  memory  of  the 
observer. — Suppress  these  repressive  peculiarities  and  the  rec- 
tification which  ensues  from  them ;  suspend  for  some  hours 
or  minutes  ordinary  sensations,  and  the  cohesion  of  connected 
recollections,  as  happens  in  sleep,  whether  incipient  or  com- 
plete ;  let,  as  then  happens,  the  uncolored  and  vague  image 
become  complete,  circumstantial  and  colored  ;  that  which,  in 
the  waking  state,  would  have  been  pronounced  a  simple  idea, 
becomes  first  an  hypnagogic  hallucination,  then  an  intense 
dream. — On  the  other  hand,  prolong  this  momentary  ecstacy ; 
let  it,  by  an  organic  accident,  be  repeated  of  itself,  suddenly, 
without  being  watched  for  or  desired,  in  spite  of  the  will ;  you 
will  have  hallucinations  like  those  of  Nicolai,  and,  if  the  pa- 
tient has  not  a  very  strong  mind,  you  will  have  the  visions  of 
a  madman,  like  those  shut  up  in  asylums,  or  of  a  mystic,  like 


CHAP.  II.]  OF  RECTIFICA  TION.  247 

those  of  India  or  of  the  Middle  Ages.*  Thus  the  history  of 
sleep  and  of  madness  gives  us  the  key  to  the  history  of  rea- 
son, and  of  the  waking  state. 

VIII.  Here,  again,  is  an  illusion  of  mental  optics,  which 
perishes  at  the  touch  of  analysis.  With  respect  to  those  con- 
ceptions and  imaginations  which  we  pronounce  internal,  we 
have  just  seen  by  what  repressive  mechanism  they  appear  to 
us  as  such.  Thanks  to  this  repression,  they  appear  to  us  as 
they  are,  that  is  to  say,  no  longer  as  external  objects  or  as 
future  and  past  events,  but  as  events  wrongly  provided  with 
this  false  appearance,  actually  internal  and  present.  I  think 
of  a  line  of  poplars,  and,  as  I  follow,  with  closed  eyes,  the 
green  curtain  of  waving  leaves,  pierced  here  and  there  by  the 
sky,  I  know  very  well  that  it  is  internal  and  present.  This 
knowledge  or  cognition  is  called  consciousness,  since  its  object 
is  internal  and  present ;  it  is  thus  opposed  to  cognitions  whose 
object  is  not  present  or  is  not  internal ;  on  this  account,  we 
separate  it  from  external  perception  and  from  memory,  and 
make  of  it  a  distinct  department,  presided  over  by  a  distinct 
faculty.  All  this  is  permissible,  and  even  convenient. — But 
here  the  error  creeps  in  ;  we  are  duped  by  the  same  words 
and  in  the  same  fashion,  as  with  respect  to  memory  and  ex- 
ternal perception  ;  as  a  cognition  is  in  question,  we  wish  abso- 
lutely to  find  an  act  of  knowledge  and  an  object  known  ;  we 
picture  consciousness  as  the  glance  of  an  internal  eye,  directed 
to  a  present  internal  event,  just  as  we  picture  memory  as  the 
glance  of  an  internal  eye  directed  to  a  past  event.  Meta- 
phors lend  their  aid ;  in  fact,  psychologists  continually  speak 
of  consciousness  as  of  a  spectator  or  internal  witness  which  ob- 
serves, compares,  takes  notes  on  the  various  conceptions, 
imaginations,  and  representations  passing  in  review  before  it. 
The  truth  is  that  in  such  a  case  there  are  not  two  events  in 
my  mind,  my  conception  on  the  one  hand,  and,  on  the  other, 
an  act  by  which  I  am  acquainted  with  it,  but  one  single  event, 
my  conception  itself.  We  split  it  in  two  because  it  has  two 
phases,  the  first,  in  which  it  appears  an  external  object  or  past 


*  See,  among  other  records,  Bunyan's  "  Autobiography,"  the  "  Vita  Nuova  "  of 
Dante,  and  the  works  of  Saint  Theresa  (Tr.  Arnauld  d' And  illy). 


248  GENERAL  MECHANISM  OF  KNOWLEDGE.       [BOOK  I. 

event,  curtain  of  poplar  leaves  or  anterior  visual  sensation,  the 
second,  in  which,  being  rectified,  it  appears  an  internal  and 
present  event,  an  optical  phantom,  then  included  in  ourselves. 
In  this  splitting,  when  we  have  laid  on  the  one  side  the  phan- 
tom with  all  its  distinctive  characters,  we  have  nothing  left  to 
constitute,  on  the  other  hand,  the  act  of  cognition.  This  act 
is  empty  ;  thence  it  happens  that  we  consider  it  pure,  simple, 
and  spiritual :  the  mistake  is  precisely  that  which  we  fell  into 
just  now  respecting  external  perception  and  memory. — In 
fact,  here  as  before,  the  internal  event  is  reduced  to  the  in- 
ternal conception,  representation,  or  present  phantom ;  the 
knowledge  that  it  is  such,  that  is  to  say  present,  internal,  and 
visionary,  is  nothing  more  than  the  rectification  or  negation 
by  which  it  is  excluded  from  the  outer  world,  from  the  future, 
and  from  the  past. 

We  can  now  seize,  with  a  general  glance,  on  the  process 
employed  by  Nature  to  create  in  us  our  first  and  principal 
sources  of  knowledge.  In  two  words,  she  creates  illusions 
and  rectifications  of  illusion,  hallucinations  and  repressions  of 
hallucination. — On  the  one  hand,  with  sensations  and  images 
combined  in  clusters  according  to  laws  we  shall  presently  see, 
she  constructs  within  us  phantoms  which  we  take  for  exter- 
nal objects,  in  most  cases  without  being  misled,  since  there 
are,  in  fact,  external  objects  corresponding  to  them,  some- 
times, by  mistake,  since  sometimes  the  corresponding  exter- 
nal objects  are  not  there ;  in  this  way  she  produces  external 
perceptions  which  are  true  hallucinations,  and  hallucinations, 
strictly  so  called,  which  are  false  external  perceptions. — On 
the  other  hand,  by  attaching  to  an  hallucination  stronger  con- 
tradictory hallucination,  she  alters  the  appearance  of  the  first 
by  a  more  or  less  radical  negation  or  rectification ;  by  this 
adjunction  she  constructs  repressed  hallucinations  which,  ac- 
cording to  the  kind  and  degree  of  their  miscarriage,  sometimes 
constitute  recollections,  sometimes  previsions,  sometimes  con- 
ceptions and  imaginations,  strictly  so  called,  all  of  which,  when 
the  repression  ceases,  become  transformed,  by  a  spontaneous 
development,  into  complete  hallucinations. — To  form  com- 
plete hallucinations  and  repressed  hallucinations,  but  in  such  a 
way  that,  when  awake  and  in  the  normal  state,  these  phan- 


CHAP.  II.]  OF  RECTIFICA  TION. 

toms  usually  correspond  to  real  things  and  events,  and  thus 
constitute  cognitions,  this  is  the  problem.  We  shall  see  how 
images  and  sensations  furnish  the  materials,  and  how  the 
laws  of  their  origin,  revival,  and  association  construct  the  edi- 
fice. 


250  THE  KNOWLEDGE   OF  BODIES,  [BOOK  II. 


BOOK  II. 

THE  KNOWLEDGE  OF  BODIES. 


CHAPTER  I. 

EXTERNAL  PERCEPTION  AND  THE  IDEA  OF  WHICH  THE  IDEA 
OF  BODY   IS   COMPOSED. 

I.  To  begin  with  the  knowledge  of  bodies.  What  is  there 
within  us  when  we  take  cognizance  by  our  sensations  of  an 
external  body — when,  for  instance,  experiencing  tactile  and 
muscular  sensations  of  cold,  of  considerable  resistance,  of 
smooth  and  uniform  contact  in  my  hand,  I  conclude  that  it 
is  resting  on  marble ;  when,  casting  my  eyes  in  a  certain  di- 
rection and  having  through  the  retina  a  sensation  of  reddish 
brown,  I  conclude  that  there  is  a  round  mahogany  table  three 
paces  from  my  eyes  ?  A  phantom  or  hallucinatory  semblance. 
—The  reader  has  already  seen  the  main  proof  of  this.*  But 
the  paradox  is  so  great  that  it  will  be  well  to  present  it  anew, 
adding  to  it  the  complementary  proofs. 

In  order  to  establish  that  external  perception,  even  when 
accurate,  is  an  hallucination  ;  it  is  sufficient  to  observe  that  its 
first  phase  is  a  sensation. — In  fact,  a  sensation,  and  notably 
a  tactile  or  visual  sensation,  engenders,  by  its  presence  alone, 
an  internal  phantom  which  appears  an  external  object. 
Dreams,  hypnotism,  hallucinations  strictly  so  called,  all  sub- 
jective sensations  are  in  evidence  as  to  this.  It  matters  little 
whether  the  sensation  be  purely  cerebral  and  arise  sponta- 
neously, without  preliminary  excitation  of  the  peripheral  ex- 
tremity of  the  nerve,  in  the  absence  of  the  objects  which 
usually  produce  this  excitation.  As  soon  as  ever  the  sensa- 
tion is  present,  the  rest  follows;  the  prologue  entails  the 


*  Part  ii.  book  i.  chap,  i,  p.  221. 


CHAP.  I.]  EXTERNAL  PERCEPTION. 

drama.  The  patient  imagines  that  he  feels  in  his  mouth  the 
melting  pulp  of  an  absent  orange,  or  the  cold  pressure  on 
his  shoulder  of  a  hand  which  is  not  there,  that  he  sees  a  num- 
ber of  passers-by  in  an  empty  street,  or  hears  clearly  articu- 
lated sounds  in  his  silent  chamber. — When,  therefore,  the  sen- 
sation arises  in  consequence  of  its  usual  antecedents,  that  is 
to  say  after  the  excitation  of  the  nerve  and  through  the  ef- 
fect of  an  external  object,  it  begets  the  same  internal  phantom, 
and  necessarily,  this  phantom  appears  an  external  object. 
Consequently,  if  there  are  actually  persons  about  in  the  street, 
the  sensation  I  shall  experience  in  looking  at  them  will  excite 
in  me,  as  before,  phantoms  of  persons  about  in  the  street,  and 
necessarily,  as  before,  these  purely  internal  phantoms  will  ap- 
pear to  me  external  objects,  that  is  to  say  real  and  true  per- 
sons. Hence  we  see  that  the  objects  we  touch,  see,  or  per- 
ceive by  any  one  of  our  senses,  are  nothing  more  than  sem- 
blances or  phantoms  precisely  similar  to  those  which  arise  in 
the  mind  of  a  hypnotized  person,  a  dreamer,  a  person  labor- 
ing under  hallucinations,  or  afflicted  by  subjective  sensations. 
The  sensation  being  given,  the  phantom  is  produced  :  it  is 
produced,  then,  whether  the  sensation  be  normal  or  abnormal ; 
it  is  produced,  then,  in  perception  where  there  is  nothing  to 
distinguish  it  from  the  real  object,  just  as  in  sickness  where 
every  thing  distinguishes  it  from  the  real  object. 

If  its  existence  be  established  by  its  antecedents,  it  is 
confirmed  by  its  consequents.  In  fact,  external  perception 
leaves  a  semblance  behind  it ;  when  we  have  seen  some  in- 
teresting object,  heard  some  fine  music,  felt  a  body  of  pecu- 
liar texture,  not  only  does  the  image  of  our  sensation  sur- 
vive the  sensation,  but  more  than  this,  it  is  accompanied  by 
a  more  or  less  energetic  and  clear  conception,  representation, 
or  phantom  of  the  object  perceived.  Suppose  this  represen- 
tation very  intense,  it  borders  on  hallucination  ;  if  sleep  is 
drawing  on,  it  becomes  a  complete  hallucination  ;  in  fact,  this 
is  its  natural  ending  ;  we  have  seen  that,  when  checked,  it  is  by 
means  of  a  supervening  repression  or  rectification  which,  at  the 
first  moment,  was  absent.  Therefore,  at  the  first  moment,  that 
is  to  say  during  external  perception,  it  was  not  checked  ;  there 
was,  then,  a  complete  hallucination,  of  which  the  preserved 


252  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

conception,  the  floating  representation,  the  posthumous  phan- 
tom, is  the  remnant.  In  this  state  and  at  this  second  moment 
we  distinguish  the  phantom,  which  at  the  first  moment  we  had 
confounded  with  the  real  object. 

There  are  other  cases,  again,  in  which  we  can  contrive,  di- 
rectly, to  separate  them  ;  such  are  the  various  errors  of  exter- 
nal perception,  above  all,  those  of  the  touch  and  of  sight.  I 
am  not  speaking  of  those  alone  which  proceed  from  purely 
subjective  sensations ;  it  is  abundantly  clear  that  in  such 
cases  the  apparent  object  is  distinct  from  any  real  object,  since 
no  real  object  exists.  I  am  speaking  of  those  proceeding 
from  ill-interpreted  sensations ;  in  which  cases  there  is  a  real 
object,  though  it  differs  from  the  apparent  object.  For  in- 
stance, when  we  close  our  eyes  and  touch  a  marble  with  the 
forefinger  and  ring-finger  crossing  one  another,  we  imagine 
ourselves  to  be  touching  two  marbles ;  this  is  one  of  the  fal- 
lacies of  touch.  Those  of  sight  are  innumerable  ;  we  fall  into 
them  daily  in  ordinary  life,  and  may  fabricate  them  at  will  by 
optical  instruments ;  by  means  of  the  stereoscope  we  give  to 
two  plane  surfaces  the  appearance  of  a  single  body  possessed 
of  relief,  and  there  are  a  hundred  analogous  illusions.  Take 
the  simplest  of  all,  that  produced  by  a  figure  reflected  in  a 
looking-glass ;  if  the  glass  is  without  any  flaw  and  fills  up  the 
whole  side  of  a  room,  if  the  light  is  well  arranged,  and  we  do 
not  know  the  circumstances,  we  shall  imagine  that  we  see  a 
figure  before  our  eyes  at  a  spot  where  there  is  nothing  but  a 
wall.  Now,  in  this  and  in  all  similar  instances,  what  we  take 
for  the  real  object  differs  from  the  real  object  ;  the  thing  af- 
firmed is  nothing  more  than  something  apparent,  there  is  noth- 
ing corresponding  to  it  at  the  spot  and  with  the  characters 
assigned ;  in  other  words,  it  is  nothing  more  than  a  simple, 
internal,  ephemeral  semblance  which  forms  part  of  ourselves, 
and  which,  nevertheless,  appears  to  us  an  external  thing,  other 
than  ourselves,  and  permanent. — But  when  our  perception 
was  free  from  error,  the  operation  was  precisely  the  same  ; 
consequently,  when  our  perception  was  free  from  error,  we 
produced  and  projected,  in  a  similar  way,  to  the  indicated 
spot,  an  apparent  object,  an  internal  and  transient  semblance 
forming  part  of  ourselves,  and  which,  nevertheless,  seemed  to 


CHAP.  I.]  EXTERNAL  PERCEPTION.  253 

be  a  body  external  to  us,  independent  and  stable.  The  only 
difference  is  that,  in  the  first  case,  there  was  an  independent 
body,  external  and  stable,  which  actually  and  rigorously  cor- 
responded to  our  semblance,  and  that  now,  this  actual  and 
rigorous  correspondence  no  longer  takes  place.  Consequent- 
ly, in  the  first  case,  we  could  not  distinguish  the  semblance  and 
the  body,  and  now  we  are  able  to  do  so. 

Thus,  there  are  three  marks  which  indicate  to  us  the 
presence  of  the  semblance,  even  in  accurate  external  percep- 
tion.— In  the  first  place,  its  exciting  and  sufficient  condition, 
the  sensation,  is  found  there  ;  it,  then,  must  necessarily  be 
there. — In  the  second  place,  we  find  it  surviving  an  instant 
afterwards,  and  repressed  by  an  added  rectification  ;  it  was 
there,  then,  an  instant  before,  and  was  not  repressed,  that  is 
to  say,  was  fully  hallucinatory. — In  the  third  place  we  dis- 
tinguish it  in  many  instances,  and,  to  effect  this,  it  is  suffi- 
cient if  the  characters  of  the  real  object  do  not  all  perfectly 
coincide  with  those  of  the  semblance ;  consequently  we  are 
forced  to  admit  its  existence,  even  when  the  perfect  coinci- 
dence of  all  its  characters  with  all  those  of  the  real  object 
prevents  our  establishing,  by  subsequent  experience,  any 
difference  between  it  and  the  real  object. — What  is  this  real 
object?  Is  there  one?  And,  if  we  recognize  one,  on  what 
can  we  found  our  recognition  ?  We  shall  presently  look  for 
answers  to  all  these  questions. — Meanwhile,  let  us  simply 
postulate  that  when  we  perceive  an  object  by  the  senses, 
when  we  see  a  tree  ten  paces  from  us,  when  we  take  a  marble 
in  our  hand,  our  perception  consists  in  the  rising  up  of  an 
internal  phantom  of  the  tree  or  marble,  and  this  phantom 
appears  to  us  an  external,  independent,  durable  thing,  sit- 
uated,- in  the  one  case,  at  ten  paces  from  us,  in  the  other 
case,  in  our  hand. 

II.  In  what  does  this  internal  phantom  consist  ? — It  is 
plain  that,  among  other  elements,  it  comprises  an  affirmative 
conception.  When  I  see  the  tree  or  touch  the  marble,  my 
sensation  suggests  to  me  a  judgment,  that  is  to  say  a  con- 
ception and  an  affirmation.  I  conceive  and  I  affirm,  that  at 
ten  paces  from  me  is  a  being  possessed  of  certain  properties, 
that  in  my  hand  is  another  such  being,  and  the  sufferer  from 


254  THE    KNOWLEDGE   OF  BODIES.  [BOOK  II. 

hallucination,  who  has  the  sensation  of  an  absent  tree  or  of 
an  absent  marble,  comes  to  the  same  conclusion.  Here  we 
have  an  essential  element  of  the  internal  semblance  ;  there 
is  no  external  perception  or  hallucination  which  does  not 
contain  an  affirmative  conception,  the  affirmative  conception 
of  a  being,  thing,  or  substance  possessed  of  properties.  Let 
us  analyze  this  conception,  and  attempt  to  mark,  one  by  one, 
the  distinct  and  connected  conceptions  of  which  it  is  the  ag- 
gregate. 

Take  the  case  of  a  mahogany  table  to  which  I  direct  my 
eyes ;  when  I  perceive  it,  I  have,  with  regard  to  rhy  retinal 
sensation,  an  affirmative  conception,  which  is  that  of  some- 
thing extended,  resisting,  hard,  polished,  feebly  sonorous, 
of  a  reddish  brown  color,  of  certain  size  and  shape,  in  short,  of 
a  being  or  substance  possessed  of  the  above-mentioned  quali- 
ties or  properties.  Let  the  reader  consider  for  a  moment : 
here,  as  in  every  proposition,  the  substance  is  equivalent  to 
the  indefinite  series  of  its  known  or  unknown  properties. 
Take  away  all  the  properties,  without  a  single  exception,  ex- 
tension, resistance,  weight,  hardness,  polish,  sonorousness, 
figure,  and  lastly,  the  most  general  of  all,  existence  itself;  it 
is  plain  that  there  will  be  nothing  left  of  the  substance ;  it  is 
the  aggregate  of  which  the  properties  are  the  details ;  it  is 
the  whole  of  which  the  properties  are  the  extracts ;  take 
away  all  the  details,  there  will  be  nothing  left  of  the  aggre- 
gate ;  take  away  all  the  extracts,  there  will  be  nothing  left 
of  the  whole.  The  rule  is  general  that — in  every  proposi- 
tion the  attributes  form  the  analysis  of  the  subject,  and 
the  subject  is  the  sum  of  the  attributes. — Consequently,  my 
conception  of  substance  is  nothing  more  than  a  summary ;  it 
is  equivalent  to  the  sum  of  the  conceptions  composing  it,  just 
as  a  number  is  equivalent  to  the  sum  of  the  units  composing 
it,  or  an  abbreviatory  sign  to  the  things  it  abbreviates  and 
signifies.  Consequ  ntly,  what  I  apply  and  attribute  to  the 
substance  is  applicable  and  attributable  to  its  equivalent. 
When,  then,  I  say  that  it  is  a  being,  a  substance,  or  in  other 
words  that  it  is,  and  that  it  subsists,  this  means  that  its  prop- 
erties are,  and  subsist.  To  conceive,  then,  and  affirm  a  sub- 
stance, is  to  conceive  and  affirm  a  group  of  properties  as  per- 


CHAP.  I]  EXTERNAL   PERCEPTION.  255 

manent  and  stable  ;  I  say  a  group  :  for  the  properties  which 
constitute  a  body  are  not  an  arbitrary  collection,  a  t^ap 
piled  up  at  will,  like  a  number  of  units,  which  I  collect  as  I 
please  and  denote  by  a  cipher  ;  they  are  not  merely  an  added 
sum,  but  more  than  this,  they  form  a  cluster.  Any  one  of  them 
involves  the  rest :  the  squared  form,  the  reddish  color,  the 
feeble  sonorousness,  the  polish,  the  hardness,  combine  to- 
gether in  the  table ;  the  perfumed  smell,  the  rosy  color,  the 
semi-globular  form,  the  softness,  combine  together  in  the 
rose.  In  fact,  whenever  I  experience  them  they  are  all  com- 
bined, and  it  is  enough  for  me  to  ascertain  the  existence  of 
one  of  them  by  one  of  my  senses,  smell  by  the  sense  of  smell, 
color  by  the  sight,  to  have  the  right  to  affirm  the  simultaneous 
presence  of  the  others  whose  existence  I  have  not  ascertained. 
It  is  this  cluster  which  forms  the  body. 

III.  Let  us  follow  out  successively  the  different  threads. 
In  what  do  the  properties  of  a  body  consist  ? — With  the  ma- 
jority of  them,  the  answer  is  easy.     They  are  relative,  relative 
to  my  sensations,  and  to  the  sensations  of  every  other  being 
analogous  to  myself:  they  are  nothing  more  than  a  power, 
the  power  of  the  body  in  question  to  excite  certain  particu- 
lar sensations. — The  rose  has  a  certain  smell,  differing  from 
that  of  the  lily  and  from  that  of  the  violet ;  this  means  that 
it  is  capable  of  exciting  in  me,  and  in  every  other  being  con- 
structed as  I  am,  a  certain  agreeable  sensation  distinct  from 
other  sensations  of  smell,  and  which  we  term  the  smell  of  the 
rose. — Sugar  has  a  certain  taste  ;  this  again  means  that  it  is 
capable  of  exciting  in  me  and  in  every  other  being  similar  to 
me,  a  certain  special  sensation  of  taste  which  we  term  a  sug- 
ary taste. — And  so  it  evidently  is  with  colors  and  sounds.     A 
certain  vibrating  cord  gives  a  sound  of  a  particular  acuteness, 
a  particular  tone,  and  a  particular  intensity.     A  certain  body 
when  illuminated  gives  a  color   of  certain  tint  and  certain 
brightness.     This  means  that  the  vibrating  cord  is  capable 
of  exciting  a  certain  particular  sensation  of  sound,  that  the 
illuminated  body  is  capable  of  exciting  a  particular  determi- 
nate sensation  of  color. — No  doubt,  in  the  present  day  we 
know  more  than  this  ;  optics  and  acoustics  have  taught  us 
that  to  a  particular  sound  there  correspond  a  particular  num- 


256  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

her  of  vibrations  of  air,  and  to  a  particula  color,  a  particular 
number  of  vibrations  of  ether.  But  this  is  not  the  primi- 
tive or  ordinary  judgment ;  it  is  necessary  to  become  scienti- 
fic before  we  can  form  it ;  the  explanation  is  subsequent  and 
superadded. — Besides,  the  difficulty  is  only  shifted :  when 
provided  with  the  theory,  we  say  that  the  molecules  of  air  or 
ether  have  the  power  of  exciting  in  us,  by  their  oscillations,  sen- 
'  sations  of  sound  or  color.  This  power  which  the  spontaneous 
judgment  ascribed  to  the  illuminated  body,  and  to  the  vibra- 
ting cord,  is  now  referred  to  the  interposed  molecules  of  air 
or  ether ;  thus  the  color  and  sound  still  remain  relative  prop- 
erties ;  whether  we  attribute  them  to  the  vibrating  cord  and 
the  illuminated  body,  or  to  the  particles  of  air  and  ether,  they 
are  nothing  more  than  the  power  of  exciting  in  us  certain 
particular  sensations. 

Finally,  if  we  pass  from  the  four  special  senses  to  the 
last  and  most  general  of  all,  that  is  to  say  to  touch, 
our  conclusions  are  similar. — In  the  first  place,  it  is  clear 
that  heat  and  cold  are  nothing  more  than  the  power  of 
exciting  sensations  of  that  name. — So  is  it  with  solidity  or 
resistance,  which  is  nothing  more  than  the  power  of  exciting 
the  muscular  sensation  of  resistance.  "When  we  contract 
the  muscles  of  our  arm,  either  by  an  exertion  of  will,  or 
by  an  involuntary  discharge  of  our  spontaneous  nervous 
activity,  the  contraction  is  accompanied  by  a  state  of  sensa- 
tion, which  is  different  according  as  the  locomotion  conse- 
quent on  the  muscular  contraction  continues  freely,  or  meets 
with  an  impediment. — In  the  former  case,  the  sensation  is 
that  of  motion  through  empty  space.  After  having  had  (let 
us  suppose)  this  experience  several  times  repeated,  we  sud- 
denly have  a  different  experience  :  the  series  of  sensations  ac- 
companying the  motion  of  our  arm  is  brought,  without  inten- 
tion or  expectation  on  our  part,  to  an  abrupt  close.  This 
interruption  would  not,  of  itself,  necessarily  suggest  the  be- 
lief in  an  external  obstacle.  The  hindrance  might  be  in  our 
organs  ;  it  might  arise  from  paralysis,  or  simple  loss  of  power 
through  fatigue.  But  in  either  of  these  cases,  the  muscles 
would  not  have  been  contracted,  and  we  should  not  have  had 
the  sensation  which  accompanies  their  contraction.  We  may 


CHAP.  I.]  EXTERNAL  PERCEPTION.  257 

have  had  the  will  to  exert  our  muscular  force,  but  the  exer- 
tion has  not  taken  place. — If  it  does  take  place,  and  is  accom- 
panied by  the  usual  muscular  sensation,  but  the  expected  sen- 
sation of  locomotion  does  not  follow,  we  have  what  is  called 
the  feeling  of  Resistance,  or  in  other  words,  of  muscular  mo- 
tion impeded."* — Later  on,  when  we  have  acquired  the  idea 
of  our  limbs,  we  shall  translate  such  an  uninterrupted  series 
of  muscular  sensations  by  the  idea  of  an  unimpeded  move- 
ment of  our  arm,  and  we  shall  translate  the  same  series  of 
sensations,  when  interrupted,  by  the  idea  of  the  hindered 
movement  of  our  arm.  In  fact,  the  one  is  capable  of  replac- 
ing the  other ;  when  once  our  senses  are  instructed,  we  dis- 
cover that  a  particular  series  of  muscular  sensations  evidenced 
by  consciousness  is  equivalent  to  a  particular  movement  of 
our  hand  evidenced  by  our  eyes  or  touch  ;  we  substitute  the 
second  fact  for  the  first,  as  being  more  convenient  to  imagine 
and  more  generally  applicable  to  nature,  and  henceforth,  we 
define  resistance  as  the  power  of  arresting  the  movement  of 
our  arm,  and  in  general  of  any  body  whatever. — But  this  is 
an  ulterior  conception.  Primitively,  resistance  is  nothing 
more  to  us  than  the  power  to  arrest  a  commenced  series  of 
muscular  sensations,  and  the  other  tactile  qualities  are  reduci- 
ble like  resistance,  to  the  power  of  exciting  some  tactile  or  mus- 
cular sensation  more  or  less  simple  or  compound,  some  mode 
or  modification  of  a  muscular  and  tactile  sensation,  or  of  a 
series  of  such  sensations. — A  body  is  smooth  or  rough  ;  which 
means  that  it  is  capable  of  exciting  a  uniform  and  soft  sensa- 
tion of  contact,  or  an  irregular  and  harsh  sensation  of  contact. 
Heavy,  light,  sharp,  level,  hard,  soft,  sticky,  damp,f  all  these 
terms  denote  nothing  more  than  the  power  of  exciting  more 
or  less  complex,  intense,  and  varied  sensations  of  contact,  of 
pressure,  of  temperature,  of  muscular  contraction,  and  of 
pain. 

IV.  There  remain  a  group  of  properties  which  seem  at 
first  sight  intrinsic  and  personal  to  bodies,  and  not  merely 
relative  to  sensations ;  such  are  extension,  form,  mobility, 

*  J.  S.  Mill,  "  Examination  of  Sir  W.  Hamilton's  Philosophy,"  219. 
\   Experiments  of  Landry,  Gratiolet,  Fick,  and  Bain.     See  part  i.  book  iii. 
chap.  2,  ante,  p.  138. 

17 


258  THE   KNOWLEDGE   OF  BODIES.  [BOOK  II. 

situation,  and  all  geometrical  properties.  And,  in  fact,  it  is 
by  means  of  such  as  these  that  we  explain  the  different  pow- 
ers we  have  just  described ;  we  conceive  and  suppose  little 
bodies  with  extension  and  shape  which  we  term  molecules ; 
we  assume  that  they  move  in  a  certain  direction  and  with 
certain  velocities ;  that  two  given  molecules  continue  to  ap- 
proach or  to  separate  from  each  other  with  more  or  less  speed 
according  to  their  reciprocal  distance  ;  that  a  collection  of 
molecules,  whose  movements  are  mutually  annulled  or  com- 
pensated, form  a  stable  body,  whose  equilibrium  becomes  al- 
tered by  the  approach  of  another  similarly  constituted  body. 
Such  is  our  idea  of  body,  a  fully  reduced  and  abstract  idea ; 
this  is  to  us  the  essential  and  indispensable  part  of  a  body; 
in  what  do  these  properties  consist  ? 

We  must  first  observe  that  they  are  reducible  to  a  princi- 
pal property,  extension,  and  to  one  of  the  powers  enumerated 
above,  resistance. — A  body  is  a  solid  or  resisting  extension ; 
that  is  to  say,  an  extension  capable  of  exciting,  in  all  its  con- 
tinuous and  successively  explored  portions,  the  sensation  of 
resistance  ;  if  not  in  us,  at  all  events  in  a  being  with  acuter 
senses  than  ours.  By  this,  solid  extension  is  distinguished 
from  empty  extension  ;  that  is  to  say  from  the  place  it  occu- 
pies. By  this,  again,  we  define  mobility,  which  is  nothing 
more  than  the  power  of  changing  place.  Finally,  by  this,  we 
define  its  limits.  It  has  a  surface,  that  is  to  say,  a  limit ;  the 
surface  is  the  limit  of  solid  extension,  as  the  line  is  the  limit 
of  the  surface,  and  the  point  the  limit  of  the  line.  Now,  limit 
means  cessation ;  the  surface,  the  line,  the  point,  and  the  fig- 
ures derived  from  them,  are  nothing  more  than  aspects  of 
solidity,  various  modes  of  considering  its  cessation  and  its 
absence ;  that  is  to  say,  the  absence  and  the  cessation  of  the 
sensation  of  resistance.— Extension  itself  remains.  We  may 
consider  it  in  three  aspects,  according  to  three  dimensions,  in 
length,  breadth,  and  height.  Take  the  case  of  a  cube  ;  its  ex- 
tension in  length,  breadth  and  height,  is  the  distance  separa- 
ting a  point  taken  at  one  of  its  angles  from  three  points  taken 
at  three  other  angles.  Distance  in  three  senses  or  directions 
is  the  foundation  of  our  idea  of  extension.  Here  we  need 


CHAP.  I.]  EXTERNAL  PERCEPTION. 

only  reproduce  the  admirable  analysis  of  the  latest  English 
philosophers.* 

When  I  contract  one  of  my  muscles,  I  experience  one 
of  those  sensations  we  term  muscular,  and  I  may  consider 
this  from  two  points  of  view. — In  the  first  place,  my  sensa- 
tion is  more  or  less  powerful ;  it  is  extreme,  if  the  effort  ap- 
proaches a  strain  of  the  muscle ;  its  limit  is  the  pain  termed 
cramp  ;  its  character  is  of  greater  or  less  intensity,  and  I  can 
compare  my  sensation  in  this  respect  with  other  more  or  less 
intense  sensations  of  the  same  muscle.  Thus  regarded,  it 
enables  me  to  estimate  the  resistance  which  other  bodies 
oppose  to  me;  but  as  yet,  teaches  me  nothing  respecting 
their  extension,  distance,  and  position. — But  there  is  a  second 
point  of  view,  and  to  this  we  owe  our  idea  of  extension.  For 
muscular  sensations  vary  not  only  in  greater  or  less  intensity, 
but  also  in  greater  or  less  duration.  "  When  a  muscle  begins 
to  contract,"  says  Mr.  Bain,  "  or  a  limb  to  bend,  we  have  a 
distinct  sense  of  how  far  the  contraction  and  the  bending  are 
carried ;  there  is  something  in  the  special  sensibility  that 
makes  one  mode  of  feeling  for  half  contraction,  another  mode 
for  three-fourths,  and  another  for  total  contraction."  Thus  we 
distinguish  in  the  sensation,  not  only  an  increase  of  intensity, 
but  also  an  increase  of  duration.  "  Suppose  a  weight  raised  by 
the  flexing  of  the  arm,  first  four  inches,  and  then  eight  inches." 
We  shall  obviously  distinguish  the  second  sensation  from  the 
first,  and,  in  the  first  place,  clearly,  because,  other  things  being 
equal,  the  second  lasts  twice  as  long  as  the  first,  and  then, 
probably,  because  in  the  second  period  of  effort,  other  muscles 
coming  into  play,  produce  new  muscular  sensations,  which 
add  themselves  on  to  the  continuation  of  the  first  sensations, 
not  only  by  prolonging,  but  also  by  diversifying  the  operation. 
By  these  two  distinct  sensations,  we  distinguish  the  greater 
or  less  amplitude  of  our  two  movements ;  and  we  see  how  we 
can  in  a  general  manner  distinguish  the  amplitude  of  one  of 
our  movements  compared  with  another. — It  is  by  means  of 
this  muscular  discernment  that  we  arrive  at  a  knowledge  of 


*  Bain,  "  Senses  and  Intellect,"  99  and  199.     Herbert  Spencer,  "  Principles  of 
Psychology,"  1st  Edition,  304.  J.  S.  Mill,  "  Examination,"  etc.,  222. 


26o  THE      KNOWLEDGE  OF  BODIES.  [BOOK  II. 

extension  and  space.  For,  "in  the  first  place  it  gives  the 
feeling  of  linear  extension,  inasmuch  as  this  is  measured  by  the 
sweep  of  a  limb,  or  other  organ  moved  by  muscles.  The 
difference  between  six  inches  and  eighteen  inches  is  express- 
ed to  us  by  the  different  contraction  of  some  one  group  oi  mus- 
cles ;  those  for  example  that  flex  the  arm,  or,  in  walking,  those 
that  flex  or  extend  the  lower  limb.  The  inward  impression 
corresponding  to  the  outward  fact  of  six  inches  in  length,  is 
an  impression  arising  from  the  continued  shortening  of  a  mus- 
cle, a  true  muscular  sensibility.  It  is  the  impression  of  a  mus- 
cular effort  having  a  certain  continuance  ;  a  greater  length 
produces  a  greater  continuance " — Now,  "  the  discrim- 
ination of  length  in  any  one  direction  includes  extension  in 
any  direction.  Whether  it  be  length,  breadth,  or  height,  the 
perception  has  precisely  the  same  character.  Hence  super- 
ficial and  solid  dimensions,  the  size  or  magnitude  of  a  solid 

object,  come  to  be  felt  in  a  similar  manner It  will  be 

obvious  that  what  is  called  situation  or  locality  must  come  under 
the  same  head,  as  these  are  measured  by  distance  taken  along 
with  direction  ;  direction  being  itself  estimated  by  distance, 
both  in  common*  observation  and  in  mathematical  theory. — In 
like  manner  form  or  shape  is  ascertained  through  the  same 
primitive  sensibility  to  extension  or  range.* — By  the  muscular 
sensiblity  thus  associated  with  prolonged  contraction  we  can 
therefore  compare  different  degrees  of  the  attribute  of  space, 
in  other  words,  difference  of  length,  surface,  situation,  and 
form.  When  comparing  two  different  lengths  we  can  feel 
which  is  the  greater,  just  as  in  comparing  two  different  weights 
or  resistances.  We  can  also,  as  in  the  case  of  weight,  acquire 
some  absolute  standard  of  comparison,  through  the  permanency 
of  impressions  sufficiently  often  repeated.  We  can  engrain 
the  feeling  of  contraction  of  the  muscles  of  the  lower  limb 
due  to  a  pace  of  thirty  inches,  and  can  say  that  some  one 
given  pace  is  less  or  more  than  this  amount.  According  to 


*  We  see  that  the  idea  of  form  is  reduced  to  that  of  position,  which  is  reduced 
to  that  of  distance.  Analytical  geometry  is  entirely  founded  on  this  observation  ; 
it  translates  form  by  the  relations  of  two  or  three  co-ordinates  representing  dis- 
tances. 


CHAP.  I.]  EXTERNAL  PERCEPTION.  26l 

the  delicacy  of  the  muscular  tissue  we  can,  by  shorter  or 
longer  practice,  acquire  distinct  impressions  for  every  stand- 
ard dimension,  and  can  decide  at  once  whether  a  given  length 
is  four  inches  or  four  and  a  half,  nine  or  ten,  twenty  or  twenty- 
one.  This  sensibility  to  size,  enabling  us  to  dispense  with 
the  use  of  measures  of  length,  is  an  acquirement  suited  to 
many  mechanical  operations.  In  drawing,  painting,  and  en- 
graving, and  in  the  plastic  arts,  the  engrained  discrimination 
of  the  most  delicate  differences  is  an  indispensable  qualifi- 
cation." 

A  third  aspect  remains  ;  for  there  are  not  merely  different 
degrees  of  intensity  and  duration,  but  different  degrees  of  ve- 
locity in  our  muscular  movements,  and  the  same  contraction 
of  the  same  muscles  excites  in  us  two  different  muscular 
sensations  according  as  it  is  rapid  or  slow.  We  learn  by  ex- 
perience that  in  many  cases  these  two  distinct  sensations  are 
signs  of  the  same  movement;  in  this  they  are  equivalent. 
"A  slow  motion  for  a  long  time  is  the  same  as  a  quicker  mo- 
tion with  less  duration."  We  easily  convince  ourselves  of 
this  "  by  seeing  that  they  both  produce  the  same  effect  in 
exhausting  the  full  range  of  a  limb.  If  we  experiment  upon 
the  different  ways  of'accomplishing  a  total  sweep  of  the  arm, 
we  shall  find  that  the  slow  movements  long  continued  are 
equal  to  quick  motions  of  short  continuance,  and  we  are  thus 
able  by  either  course  to  acquire  to  ourselves  a  measure  of 
range  and  linear  extension." — "  Suppose,"  says  Mill,  "  two 
small  bodies,  A  and  B,  sufficiently  near  together  to  admit  of 
their  being  touched  simultaneously,  one  with  the  right  hand, 
the  other  with  the  left.  Here  are  two  tactual  sensations 
which  are  simultaneous,  just  as  a  sensation  of  color  and  one 
of  odor  might  be  ;  and  this  makes  us  cognize  the  two  objects 
of  touch  as  both  existing  at  once.  The  question  then  is, 
what  have  we  in  our  minds,  when  we  represent  to  ourselves 
the  relation  between  these  two  objects,  already  known  to  be 
simultaneous,  in  the  form  of  Extension  or  intervening  Space 
— a  relation  which  we  do  not  suppose  to  exist  between  the 
color  and  the  odor."  Our  answer  to  this  is  "  that  whatever 
the  notion  of  Extension  may  be,  we  acquire  it  by  passing  our 
hand  or  some  other  organ  of  touch,  in  a  longitudinal  direction 


262  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

from  A  to  B :  that  this  process,  as  far  as  we  are  conscious  of 

it,  consists  of  a  series  of  varied  muscular  sensations 

When  we  say  that  there  is  a  space  between  A  and  B,  we 
mean  that  some  amount  of  these  muscular  sensations  must  in- 
tervene ;  and  when  we  say  that  the  space  is  greater  or  less, 
we  mean  that  the  series  of  sensations  (amount  of  muscular 
effort  being  given)  is  longer  or  shorter.  If  another  object,  C, 
is  farther  off  in  the  same  line,  we  judge  its  distance  to  be 
greater,  because,  to  reach  it,  the  series  of  muscular  sensations 
must  be  further  prolonged,  or  else  there  must  be  the  increase 
of  effort  which  corresponds  to  augmented  velocity.  Now 
this,  which  is  unquestionably  the  mode  in  which  we  became 
aware  of  extension,  is  considered  by  the  psychologists  in  ques- 
tion to  be  extension.  The  idea  of  Extended  Body  they  con- 
sider to  be  that  of  a  variety  of  resisting  points,  existing  simul- 
taneously, but  which  can  be  perceived  by  the  same  tactile 
organ  only  successively,  at  the  end  of  a  series  of  muscular 
sensations  which  constitutes  their  distance ;  and  are  said  to 
be  at  different  distances  from  one  another  because  the  series 
of  intervening  muscular  sensations  is  longer  in  some  cases 
than  in  others An  intervening  series  of  muscular  sen- 
sations before  the  one  object  can  be  reached  from  the  other, 
is  the  only  peculiarity  which  (according  to  this  theory)  distin- 
guishes simultaneity  in  space  from  the  simultaneity  which 
may  exist  between  a  taste  and  a  color,  or  a  taste  and  a  smell : 
and  we  have  no  reason  for  believing  that  Space  or  Extension 
in  itself,  is  any  thing  different  from  that  which  we  recognize 
it  by."* 

Thus,  in  our  cases,  time  is  the  parent  of  space,  and  we 
conceive  simultaneous  magnitude  by  means  only  of  success- 
ive magnitude.  When  our  arm  moves,  it  traverses  a  space  ; 
but  we  do  not  estimate  the  magnitude  of  what  is  traversed 
except  by  the  two  factors  measuring  it,  on  the  one  hand  by 
the  amount  of  our  muscular  exertion,  on  the  other  hand  by 
the  duration  of  our  successive  muscular  sensations.  In  tran- 
sit through  space  there  are  three  terms — the  magnitude  of 
the  motive  force,  the  length  of  time  employed,  the  extent  of 


*  Mill,  "  Examination,"  etc.,  pp.  228-30. 


CHAP.  I.]  EXTERNAL  PERCEPTION.  263 

space  traversed — and  each  of  these  is  determined  by  the  oth- 
er two.  Now,  the  two  first  we  find  in  ourselves,  and  they 
are  together  equivalent  to  the  third,  since  the  third  is  com- 
pletely determined  by  them.  It  is  by  the  first  two,  then, 
that  the  space  traversed  is  translated  into  our  minds,  and 
such  space  is  in  itself  nothing  more  to  us  than  the  power  of 
exciting  them.  Thus,  greater  or  less  space  is  nothing  more 
than  the  power  of  exciting  in  us,  with  an  equal  amount  of 
muscular  effort,  a  longer  or  shorter  series  of  successive  mus- 
cular sensations. — Add  to  this  solidity,  that  is  to  say  the 
power  of  exciting  the  sensation  of  resistance,  and  we  have 
body. — In  fact,  its  three  dimensions  are  the  three  distinct  as- 
pects to  which  all  the  sensations  measuring  its  extension  are 
reduced.  Its  continuity  is  the  power  of  exciting  the  sensa- 
tion of  resistance,  throughout  the  whole  duration  of  these 
sensations.  Its  limit  is  the  moment  at  which  the  sensation 
of  resistance  ceases.  Its  figure  is  the  aggregate  of  these  lim- 
its. We  conceive  it  as  composed  of  parts,  because  the  sen- 
sation, whose  duration  measures  it,  is  itself  composed  of  parts. 
So  too  it  is  infinitely  divisible,  because  this  duration  is  itself 
infinitely  divisible.  Though  the  elements  of  our  sensation 
be  successive,  the  elements  of  the  body  appear  to  us  as  simul- 
taneous ;  in  fact,  they  are,  as  the  body  itself,  permanent  pow- 
ers, whose  permanence,  like  that  of  the  body  itself,  is  attest- 
ed to  us  by  the  regular  return  of  the  sensations  they  excite  ; 
being  permanent,  they  are  contemporaneous  ;  though  we  per- 
ceive them  successively  they  exist  together,  and  the  succes- 
sion disjoining  their  effects  is  not  applicable  to  their  existence. 
I  pass  my  hand  several  times  heavily  along  the  side  of  the 
table,  from  left  to  right,  then  from  right  to  left,  and  always 
with  the  same  speed ;  that  is  to  say  with  the  same  amount 
of  motive  effort.  Now,  in  all  these  experiences,  the  sensation 
given  me  by  my  contracted  arm  is  the  same  in  duration,  and 
has,  as  accompaniment,  at  every  moment,  the  uniform  sen- 
sation of  resistance.  Whether  I  begin  at  the  right  or  left,  it 
does  not  matter ;  the  double  muscular  sensation  remains  the 
same  in  the  two  cases.  It  forms,  then,  a  severed  group  among 
my  recollections  and  previsions,;  it  is  distinguished  from  the 
others  by  the  precise  degree  of  intensity  of  the  first  compo- 


264  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

nent  muscular  sensation,  by  the  precise  degree  of  duration 
of  the  second  component  muscular  sensation,  and  further,  by 
the  particular  shade  of  the  conjoined  sensation  of  touch  ;  the 
power  of  exciting  this  group  is  what  we  term  the  resistance 
and  extension  of  the  table. — Hence,  we  see  that  all  the  sen- 
sible properties  of  bodies,  including  extension,  and  conse- 
quently form,  situation,  and  other  tangible  qualities,  are,  in 
final  analysis,  nothing  more  than  the  power  of  exciting  sen- 
sations. 

V.  This  leads  us  to  a  new  notion  of  the  nature  of  bodies ; 
a  body  is  a  collection  of  such  powers  as  we  have  just  described. 
But  what  are  these  powers.  ? — This  rose  has  power  to  excite  a 
certain  sensation  of  smell ;  which  means  that,  when  within 
reach  of  it,  this  sensation  of  smell  will  be  aroused.  This  table 
has  power  to  excite  a  certain  strong  sensation  of  resistance ; 
which  means  that,  if  it  is  pressed  with  the  hand,  a  strong 
sensation  of  resistance  will  be  aroused.  A  power,  then,  is 
nothing  intrinsic  and  personal  to  the  object  to  which  we  at- 
tribute it.  We  simply  mean  by  the  word  that  certain  effects 
are  possible,  future,  proximate,  necessary  under  certain  con- 
ditions. We  simply  mean,  in  this  instance,  that  certain  sen- 
sations are  possible,  future,  proximate,  necessary  under  cer- 
tain conditions.  Consequently,  a  collection  of  powers  is  noth- 
ing ;  consequently  a  body,  that  is  to  say  a  collection  of 
powers,  is  also  nothing.  At  the  foundation  of  the  affirmative 
conception,  by  which,  having  passed  and  pressed  my  hand 
over  this  table,  I  conceive  arid  affirm  an  independent  and 
permanent  body,  there  is  nothing  more  than  the  affirmative 
conception  of  analogous  muscular  and  tactile  sensations,  these 
sensations  being  conceived  and  affirmed  as  possible  for  any 
being  similar  to  myself,  who  might  come  within  their  range, 
as  future,  proximate,  certain,  and  necessary,  for  any  being  sim- 
ilar to  myself,  who  might  pass  and  press  his  hand  or  other 
organ  in  the  same  manner.  All  I  conceive  and  affirm  is 
their  possibility  under  certain  conditions,  and  their  necessity 
under  fuller  conditions.  They  are  possible  when  all  these 
conditions,  but  one,  are  given.  They  become  necessary  when 
all  these  conditions,  and  in  addition  the  missing  condition, 
are  given  ;  and  here  the  possibility  becomes  necessity,  by  the 


CHAP.  I.]  EXTERNAL  PERCEPTION.  26$ 

addition  of  the  last  condition.  This  is  what  constitutes  for  us 
the  object.  When,  with  closed  eyes,  I  experience  a  sensa- 
tion of  the  smell  of  a  rose,  and  thereupon  conceive  and  affirm' 
the  presence  of  a  rose,  I  simply  conceive  and  affirm  the  pos- 
sibility for  myself,  and  for  every  other  being  similar  to  myself, 
of  a  certain  muscular  and  tactile  sensation  of  soft  resistance, 
of  a  certain  visual  sensation  of  colored  form  ;  a  possibility 
would  become  a  necessity,  if,  to  the  existence  and  presence 
of  the  sentient  person  indicated,  were  added  a  final  condition, 
a  certain  movement  of  his  exploring  hand,  a  certain  direction 
of  his  open  eyes. — Certain  possibilities  and  certain  necessities  of 
sensations,  to  these  are  reducible  the  powers,  consequently 
the  properties,  consequently  the  very  substance  of  bodies. 

This  conclusion  seems  paradoxical.  How  can  we  admit 
that  bodies,  that  is  to  say  permanent  substances  independent 
of  us,  and  which  we  conceive  as  causes  of  our  sensations, 
are,  at  bottom,  and  in  themselves,  nothing  more  than  possi- 
bilities and  necessities  of  sensation  ? — To  remove  this  diffi- 
culty, let  us  consider  successively  the  principal  characters  of 
these  possibilities  and  necessities,  and  we  shall  see  that  they 
possess  all  the  characters  of  substance. — They  are  permanent ; 
in  fact,  the  proposition  by  which  I  affirm  the  possibility  and 
necessity  of  a  certain  sensation  under  certain  conditions  is 
general,  and  holds  good  for  all  moments  of  time.  Whatever 
be  the  moment  of  duration  I  am  considering,  this  possibility 
and  this  necessity  are  found  there ;  they  are,  then,  persistent 
and  stable. — On  the  other  hand,  they  are  independent  of  me, 
and  of  all  sentient  individuals  who  are  living,  have  lived,  or  will 
live.  For  the  proposition  by  which  I  affirm  the  possibility 
and  necessity  of  certain  sensations  under  certain  conditions 
is  abstract,  and  holds  good,  not  only  in  my  case  and  in  that 
of  every  actual  person,  but  for  all  possible  persons.  Even 
were  there  not  in  fact  any  sentient  individual  in  the  world, 
they  would  exist ;  they  exist,  then,  apart  and  by  themselves. 
—For  these  two  reasons,  they  are  opposed,  first,  to  sensa- 
tions which  are  transient  and  not,  like  them,  permanent ;  then, 
to  sentient  individuals  themselves  who  are  other  than  they. 
These  are  the  essential  characters  of  substance ;  consequently, 
there  is  nothing  astonishing  in'  our  terming  these  possibilities 


266  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

substances,  and  in  their  playing  a  predominant  part  in  our 
mind. 

Let  us  see  how  it  is  they  assume  this  part.  "  I  see  a 
piece  of  white  paper  on  a  table.  I  go  into  another  room, 
and  though  have  I  ceased  to  see  it,  I  am  persuaded  that  the 
paper  is  still  there.  I  no  longer  have  the  sensations  which 
it  gave  me  ;  but  I  believe  that  when  I  again  place  myself  in 
the  circumstances  in  which  I  had  those  sensations,  that  is, 
when  I  go  again  into  the  room,  I  shall  again  have  them  ;  and 
further,  that  there  has  been  no  intervening  moment  at  which 
this  would  not  have  been  the  case." — This  is  a  specimen  of 
the  ordinary  operations  of  our  mind,  and  it  is  plain  that  the 
analysis  would  be  the  same,  in  the  case  of  any  other  percep- 
tion of  sight,  or  of  another  sense. — Now,  in  accordance  with 
this  analysis,  it  appears  "  that  my  conception  of  the  world  at 
any  given  instant  consists,  in  only  a  small  proportion,  of 
present  sensations.  Of  these  I  may  at  the  time  have  none 
at  all,  and  they  are  in  any  case  a  most  insignificant  portion 
of  the  whole  which  I  apprehend.  The  conception  I  form  of 
the  world  existing  at  any  moment,  comprises,  along  .with  the 
sensations  I  am  feeling,  a  countless  variety  of  possibilities 
of  sensation ;  namely,  the  whole  of  those  which  past  obser- 
vation tells  me  that  I  could,  under  any  supposable  circum- 
stances, experience  at  this  moment,  together  with  an  indefi- 
nite and  illimitable  multitude  of  others  which  though  I  do 
not  know  that  I  could,  yet  it  is  possible  that  I  might  ex- 
perience in  circumstances  not  known  to  me.  These  various 
possibilities  are  the  important  thing  to  me  in  the  world.  My 
present  sensations  are  generally  of  little  importance,  and  are 
moreover  fugitive :  the  possibilities,  on  the  contrary  are  per- 
manent, which  is  the  character  that  mainly  distinguishes  our 
idea  of  Substance  or  Matter  from  our  notion  of  sensation. — 
These  possibilities,  which  are  conditional  certainties,  need  a 
special  name  to  distinguish  them  from  mere  vague  possibilities, 
which  experience  gives  no  warrant  for  reckoning  upon.  Now, 
as  soon  as  a  distinguishing  name  is  given,  though  it  be  only 
to  the  same  thing  regarded  in  a  different  aspect,  one  of  the 
most  familiar  experiences  of  our  mental  nature  teaches  us, 
that  the  different  name  comes  to  be  considered  as  the  name 
of  a  different  thing. 


CHAP.  I.]  EXTERNAL  PERCEPTION.  26/ 

"  There  is  another  important  peculiarity  of  these  certified 
or  guaranteed  possibilities  of  sensation  ;  namely,  that  they 
have  reference,  not  to  single  sensations,  but  to  sensations 
joined  together  in  groups.  When  we  think  of  any  thing  as 
a  material  substance,  or  body,  we  either  have  had,  or  we 
think  that  on  some  given  supposition  we  should  have,  not 
some  one  sensation,  but  a  great  and  even  an  indefinite  num- 
ber and  variety  of  sensations,  generally  belonging  to  different 
senses,  but  so  linked  together  that  the  presence  of  one  an- 
nounces the  possible  presence  at  the  very  same  instant  of 
any  or  all  of  the  rest.  In  our  mind,  therefore,  not  only  is 
this  particular  Possibility  of  sensation  invested  with  the 
quality  of  permanence,  when  we  are  not  actually  feeling  any  of 
the  sensations  at  all ;  but  when  we  are  feeling  some  of  them, 
the  remaining  sensations  of  the  group  are  conceived  by  us  in 
the  form  of  Present  Possibilities,  which  might  be  realized  at 
the  very  moment.  And  as  this  happens  in  turn  to  all  of 
them,  the  group  as  a  whole  presents  itself  to  the  mind  as 
permanent,  in  contrast  not  solely  with  the  temporariness  of 
my  bodily  presence,  but  also  with  the  temporary  character 
of  each  of  the  sensations  composing  the  group ;  in  other 
words,  as  a  kind  of  permanent  substratum,  under  a  set  of 
passing  experiences  or  manifestations  :  which  is  another  lead- 
ing character  of  our  idea  of  substance  or  matter,  as  distin- 
guished from  sensation. 

"  Let  us  now  take  into  consideration  another  of  the  gen- 
eral characters  of  our  experience,  namely,  that  in  addition  to 
fixed  groups,  we  also  recognize  a  fixed  Order  in  our  sensa- 
tions; an  Order  of  succession,  which,  when  ascertained  by 
observation,  gives  rise  to  the  ideas  of  Cause  and  Effect  .... 
Now,  of  what  nature  is  this  fixed  order  among  our  sensa- 
tions? It  is  a  constancy  of  antecedence  and  sequence.  But 
the  constant  antecedence  and  sequence  do  not  generally  exist 
between  one  actual  sensation  and  another.  Very  few  such 
sequences  are  presented  to  us  by  experience.  In  almost  all  the 
constant  sequences  which  occur  in  Nature, the  antecedence  and 
consequence  do  not  obtain  between  sensations,  but  between  the 
groups  we  have  been  speaking  about,  of  which  a  very  small  por- 
tion is  actual  sensation,  the  greater  part  being  permanent  pos- 


268  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

sibilities  of  sensation,  evidenced  to  us  by  a  small  and  variable 
number  of  sensations  actually  present.  Hence,  our  ideas  of 
causation,  power,  activity,  do  not  become  connected  in  thought 
with  our  sensations  as  actual  at  all,  save  in  the  few  physio- 
logical cases  where  these  figure  by  themselves  as  the  ante- 
cedents in  some  uniform  sequence.  Those  ideas  become  con- 
nected, not  with  sensations,  but  with  groups  of  possibilities 
of  sensation.  The  sensations  conceived  do  not,  to  our  ha- 
bitual thoughts,  present  themselves  as  sensations  actually  ex- 
perienced, inasmuch  as  not  only  any  one  or  any  number  of 
them  may  be  supposed  absent,  but  none  of  them  need  be 
present.  We  find  that  the  modifications  which  are  taking 
place  more  or  less  regularly  in  our  possibilities  of  sensation, 
are  mostly  quite  independent  of  our  consciousness,  and  of 
our  presence  or  absence.  Whether  we  are  asleep  or  awake 
the  fire  goes  out,  and  puts  an  end  to  one  particular  possi- 
bility of  warmth  and  light.  Whether  we  are  present  or  ab- 
sent the  corn  ripens,  and  brings  a  new  possibility  of  food. 
Hence  we  speedily  learn  to  think  of  Nature  as  made  up 
solely  of  these  groups  of  possibilities,  and  the  active  force 
in  Nature  as  manifested  in  the  modification  of  some  of  these 
by  others.  The  sensations,  though  the  original  foundation 
of  the  whole,  come  to  be  looked  upon  as  a  sort  of  accident 
depending  on  us,  and  the  possibilities  as  much  more  real 
than  the  actual  sensations,  nay,  as  the  very  realities  of  which 
these  are  only  the  representations,  appearances,  or  effects. — 
When  this  state  of  mind  has  been  arrived  at,  then,  and  from 
that  time  forward,  we  are  never  conscious  of  a  present  sen- 
sation without  instantaneously  referring  it  to  some  one  of 
the  groups  of  possibilities  into  which  a  sensation  of  that  par- 
ticular description  enters  ;  and  if  we  do  not  yet  know  to 
what  group  to  refer  it,  we  at  least  feel  an  irresistible  convic- 
tion that  it  must  belong  to  some  group  or  other ;  i.  e.  that  its 
presence  proves  the  existence,  here  and  now,  of  a  great  num- 
ber and  variety  of  possibilities  of  sensation,  without  which  it 
would  not  have  been.  The  whole  set  of  sensations  as  pos- 
sible, form  a  permanent  background  to  any  one  or  more  of 
them  that  are,  at  a  given  moment,  actual ;  and  the  possi- 
bilities are  conceived  as  standing  to  the  actual  sensations  in 


CHAP.  I.]  EXTERNAL  PERCEPTION.  269 

the  relation  of  a  cause  to  its  effects,  or  of  canvas  to  the  fig- 
ures painted  on  it,  or  of  a  root  to  the  trunk,  leaves,  and 
flowers  or  of  a  substratum  to  that  which  is  spread  over  it,  or, 
in  transcendental  language  of  Matter  to  Form. 

"  When  this  point  has  been  reached,  the  Permanent  Pos- 
sibilities in  question  have  assumed  such  unlikeness  of  aspect, 
and  such  difference  of  apparent  relation  to  us,  from  any  sen- 
sations, that  it  would  be  contrary  to  all  we  know  of  the  con- 
stitution of  human  nature  that  they  should  not  be  conceived 
as,  and  believed  to  be,  at  least  as  different  from  sensations  as 
sensations  are  from  one  another.  Their  groundwork  in  sen- 
sation is  forgotten,  and  they  are  supposed  to  be  something 
intrinsically  distinct  from  it.  We  can  withdraw  ourselves  from 
any  of  our  (external)  sensations,  or  we  can  be  withdrawn  from 
them  by  some  other  agency.  But  though  the  sensations  cease, 
the  possibilities  remain  in  existence :  they  are  independent 
of  our  will,  our  presence,  and  every  thing  which  belongs  to 
us.  We  find,  too,  that  they  belong  as  much  to  other  human 
or  sentient  beings  as  to  ourselves.  We  find  other  people 
grounding  their  expectations  and  conduct  upon  the  same  per- 
manent possibilities  on  which  we  ground  ours.  But  we  do 
not  find  them  experiencing  the  same  actual  sensations.  Other 
people  do  not  have  our  sensations  exactly  when  and  as  we 
have  them:  but  they  have  our  possibilities  of  sensation  ;  what- 
ever indicates  a  present  possibility  of  sensations  to  ourselves, 
indicates  a  present  possibility  of  sensations  to  them,  except 
so  far  as  their  organs  of  sensation  may  vary  from  the  type  of 
ours.  This  puts  the  final  seal  to  our  conception  of  the  groups 
of  possibilities  as  the  fundamental  reality  in  Nature.  The 
permanent  possibilities  are  common  to  us  and  to  our  fellow- 
creatures  ;  the  actual  sensations  are  not.  That  which  other 
people  become  aware  of  when,  and  on  the  same  grounds  as 
I  do,  seems  more  real  to  me  than  that  which  they  do  not  know 
of  unless  I  tell  them.  The  world  of  Possible  Sensations  suc- 
ceeding one  another,  according  to  laws,  is  as  much  in  other 
beings  as  it  is  in  me ;  it  has  therefore  an  existence  outside 
me ;  it  is  an  External  World. 

"  Matter,  then,  may  be  defined,  a  Permanent  Possibility 
of  Sensation We  believe  that  we  perceive  a  something 


270  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

closely  related  to  all  our  sensations,  but  different  from  those 
which  we  are  feeling  at  any  particular  minute ;  and  distin- 
guished from  sensations  altogether,  by  being  permanent  and 
always  the  same,  while  these  are  fugitive,  variable,  and  alter- 
nately displace  one  another.  But  these  attributes  of  the  ob- 
ject of  perception  are  properties  belonging  to  all  the  possibili- 
ties of  sensation,  which  experience  guarantees.  The  belief 
in  such  permanent  possibilities  seems  to  me  to  include  all  that 
is  essential  or  characteristic  in  the  belief  in  substance.  I  be- 
lieve that  Calcutta  exists,  though  I  do  not  perceive  it,  and 
that  it  would  still  exist  if  every  percipient  inhabitant  in  it 
were  suddenly  to  leave  the  place,  or  be  struck  dead.  But 
when  I  analyze  the  belief,  all  I  find  in  it  is,  that  were  those 
events  to  take  place,  the  Permanent  Possibility  of  Sensation 
which  I  call  Calcutta  would  still  remain ;  that  if  I  were  sud- 
denly transported  to  the  banks  of  the  Hooghly,  I  should  still 
have  the  sensations  which,  if  now  present,  would  lead  me  to 
affirm  that  Calcutta  exists  here  and  now.* — We  may  infer, 
therefore,  that  both  philosophers  and  the  world  at  large,  when 
they  think  of  matter,  conceive  it  really  as  a  Permanent  Possi- 
bility of  Sensation.  But  the  majority  of  philosophers  fancy 
that  it  is  something  more ;  and  the  world  at  large,  though 
they  have  really,  as  I  conceive,  nothing  in  their  minds  but  a 
Permanent  Possibility  of  Sensation,  would,  if  asked  the  ques- 
tion, undoubtedly  agree  with  the  philosophers ;  and  though 
this  is  sufficiently  explained  by  the  tendency  of  the  human 
mind  to  infer  difference  of  things  from  difference  of  names  I 
acknowledge  the  obligation  of  showing  how  it  can  be  possible 
to  believe  in  an  existence  transcending  all  possibilities  of  sen- 
sation, unless  on  the  hypothesis  that  such  an  existence  act- 
ually is,  and  that  we  actually  perceive  it. 

"The  explanation,  however,  is  not  difficult.  It  is  an  ad- 
mitted fact  that  we  are  capable  of  all  conceptions  which  can 
be  formed  by  generalizing  from  the  observed  laws  of  our  sen- 
sations. Whatever  relation  we  find  to  exist  between  any  one 


*  For  analysis  to  be  wholly  exact,  it  should  read,  I  think  : — "  If  any  being 
whatever,  analogous  to  myself,  were  transported  to  the  banks  of  the  Hooghly,  he 
would  have,  etc."  The  permanent  possibility  is  absolutely  general. 


CHAP.  I.]  EXTERNAL  PERCEPTION.  2/1 

of  our  sensations  and  something  different  from  it,  that  same 
relation  we  have  no  difficulty  in  conceiving  to  exist  between 
the  sum  of  all  our  sensations  and  something  different  from 
them.  The  differences  which  our  consciousness  recognizes  be- 
tween one  sensation  and  another  give  us  the  general  notion 
of  difference,  and  inseparably  associate  with  every  sensation 
we  have,  the  feeling  of  its  being  different  from  other  things : 
and  when  once  this  association  has  been  formed,  we  can  no 
longer  conceive  anything,  without  being  able,  and  even  being 
compelled,  to  form  also  the  conception  of  something  differ- 
ent from  it.  This  familiarity  with  the  idea  of  something  dif- 
ferent from  each  thing  we  know  makes  it  natural  and  easy  to 
form  the  notion  of  something  different  from  #// things  that  we 
know,  collectively  as  well  as  individually.  It  is  true  we  can 
form  no  conception  of  what  such  a  thing  can  be ;  our  notion 
of  it  is  merely  negative;  but  the  idea  of  a  substance,  apart 
from  its  relation  to  the  impressions  which  we  conceive  it  as 
making  on  our  senses,  is  a  merely  negative  one.  There  is 
thus  no  psychological  obstacle  to  our  forming  the  notion  of 
a  something  which  is  neither  a  sensation  nor  a  possibility  of 
sensation,  even  if  our  consciousness  does  not  testify  to  it ;  and 
nothing  is  more  likely  than  that  the  Permanent  Possibilities 
of  sensation,  to  which  our  consciousness  does  testify,  should 
be  confounded  in  our  minds  with  this  imaginary  conception. 
All  experience  attests  the  strength  of  the  tendency  to  mistake 
mental  abstractions,  even  negative  ones,  for  substantive  reali- 
ties ;  and  the  Permanent  Possibilities  of  sensation  which  ex- 
perience guarantees  are  so  extremely  unlike  in  many  of  their 
properties  to  actual  sensations,  that  since  we  are  capable  of 
imagining  something  which  transcends  sensations,  there  is  a 
great  natural  probability  that  we  should  suppose  these  to  be 
it. 

"  But  this  natural  possibilty  is  converted  into  certainty, 
when  we  take  into  consideration  that  universal  law  of  our 
experience  which  is  termed  the  law  of  Causation,  and  which 
makes  us  mentally  connect  with  the  beginning  of  every  thing 
some  antecedent  condition  or  Cause.  The  case  of  Causation 
is  one  of  the  most  marked  of  all  the  cases  in  which  we  extend 
to  the  sum  total  of  our  consciousness,  a  notion  derived  from 


272  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

its  parts.  It  is  a  striking  example  of  our  power  to  conceive, 
and  our  tendency  to  believe,  that  a  relation  which  subsists 
between  every  individual  item  of  our  experience  and  some 
other  item,  subsists  also  between  our  experience  as  a  whole, 
and  something  not  within  the  sphere  of  experience.  By  this 
extension  to  the  sum  of  all  our  experiences,  of  the  internal 
relations  obtaining  between  its  several  parts,  we  are  led  to 
conceive  sensation  itself — the  aggregate  whole  of  our  sensa- 
tions— as  deriving  its  origin  from  antecedent  existences  trans- 
cending sensation.  That  we  should  do  this,  is  a  consequence 
of  the  particular  character  of  the  uniform  sequences,  which 
experience  discloses  to  us  among  our  sensations.  As  already 
remarked,  the  constant  antecedent  of  a  sensation  is  seldom 
another  sensation,  or  set  of  sensations,  actually  felt.  It  is 
much  oftener  the  existence  of  a  group  of  possibilities,  not  nec- 
essarily including  any  actual  sensations,  except  such  as  are  re- 
quired to  show  that  the  possibilities  are  really  present.  Nor 
are  actual  sensations  indispensable  even  for  this  purpose  ;  for 
the  presence  of  the  object  (which  is  nothing  more  than  the 
immediate  presence  of  the  possibilities)  may  be  made  known 
to  us  by  the  very  sensations  we  refer  to  it  as  its  effect.  Thus, 
the  real  antecedent  of  an  effect — the  only  antecedent  which, 
being  invariable  and  unconditional,  we  consider  to  be  the 
cause — may  be,  not  any  sensation  really  felt,  but  solely  the 
presence  at  that  or  the  immediately  preceding  moment  of  a 
group  of  possibilities  of  sensation.  Hence  it  is  not  with  sen- 
sations as  actually  experienced,  but  with  their  Permanent 
Possibilities,  that  the  idea  of  Cause  comes  to  be  identified : 
and  we,  by  one  and  the  same  process,  acquire  the  habit  of  re- 
garding Sensation  in  general,  like  all  our  individual  sensations, 
as  an  Effect,  and  also  that  of  conceiving  as  the  causes  of  most 
of  our  individual  sensations,  not  other  sensations,  but  general 

possibilities  of  sensation It  may  perhaps  be  said  that 

the  preceding  theory  gives,  indeed,  some  account  of  the  idea 
of  Permanent  Existence  which  forms  part  of  our  conception 
of  matter,  but  gives  no  explanation  of  our  believing  these  per- 
manent objects  to  be  external,  or  out  of  ourselves.  I  appre- 
hend, on  the  contrary,  that  the  very  idea  of  anything  out  of 
ourselves  is  derived  solely  from  the  knowledge  experience 


CHAP.  I.]  EXTERNAL  PERCEPTION.  273 

gives  us  of  the  Permanent  Possibilities.  Our  sensations  we 
carry  with  us  wherever  we  go,  and  they  never  exist  where  we 
are  not ;  but  when  we  change  our  place  we  do  not  carry  away 
with  us  the  Permanent  Possibilities  of  Sensation :  they  re- 
main until  we  return,  or  arise  and  cease  under  conditions  with 
which  our  presence  has  in  general  nothing  to  do.  And  more 
than  all — they  are,  and  will  be  after  we  have  ceased  to  feel, 
Permanent  Possibilities  of  Sensation  to  other  beings  than  our- 
selves. Thus,  our  actual  sensations,  and  the  permanent  pos- 
sibilities of  sensation,  stand  out  in  obtrusive  contrast  to  one 
another:  and  when  the  idea  of  Cause  has  been  acquired,  and 
extended  by  generalization  from  the  parts  of  our  experience 
to  its  aggregate  whole,  nothing  can  be  more  natural  than  that 
the  Permanent  Possibilities  should  be  classed  by  us  as  exist- 
ences generically  distinct  from  our  sensations,  but  of  which 
our  sensations  are  the  effect If  all  these  considera- 
tions put  together  do  not  completely  explain  and  account 
for  our  conceiving  these  Possibilities  as  a  class  of  independ- 
ent and  substantive  entities,  I  know  not  what  psychological 
analysis  can  be  conclusive."* 

In  my  opinion,  this  is  so,  save  in  a  point  we  have  already 
indicated.  These  possibilities  of  sensation  constituted  by  the 
presence  of  all  the  conditions  of  the  sensation,  but  one,  are 
transfofmed  into  necessities,  when  this  last  absent  condition 
becomes  added  to  the  rest.  I  see  a  table  ;  which  means  that, 
having  a  particular  visual  sensation,  I  conceive  and  affirm  the 
possibility  of  certain  sensations  of  muscular  movement,  resist- 
ance, and  feeble  sound  in  every  sentient  being ;  but  it  also 
means  that  if  to  the  existence  of  a  sentient  being  we  add  a 
further  condition,  some  movement  which  will  put  his  hand  in 
contact  with  the  table,  there  will  be,  in  his  case,  no  longer  a 
simple  possibility,  but  further  than  this,  the  necessity  of  these 
sensations.  These  necessities,  set  apart  and  considered  sep- 
arately, are  what  we  call  forces.f  Force  or  necessity,  these 
two  terms  are  equivalent ;  they  indicate  that  the  event  in 
question  must  become  accomplished  ;  both  one  and  the  other 


*  Mill,  "  Examination,'*  etc.  pp.  192-205. 
f  Part  i.  book  iv.  ch.  iii.  p.  2O2. 
18 


274  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

are  particularities,  modes  of  being  extracted  from  the  event 
and  isolated  by  a  mental  fiction.  But  as  the  law  predicting 
the  event  under  certain  conditions  is  general,  and  therefore 
permanent,  both  one  and  the  other  appear  as  permanent,  and 
are  found  to  be  erected  into  substances,  which  puts  them  in 
opposition  to  transient  events  and  classes  them  apart. — At 
present,  under  the  name  of  forces,  permanent  possibilities  are 
reducible  without  difficulty  to  what  we  term  matter  and  body ; 
we  have  no  hesitation  in  admitting  that  the  world  in  which 
we  are  placed  is  a  system  of  forces ;  at  all  events,  this  is  the 
conception  of  the  most  profound  physicists.  Various  forces, 
which,  under  various  conditions,  excite  in  us  various  sensa- 
tions :  in  this  we  have  bodies  in  their  relation  to  ourselves, 
and  to  all  beings  analogous  to  us. 

VI.  What  a  body  is  with  relation  to  another  remains  to 
be  investigated. — We  must  first  observe  that  the  majority  of 
bodies  which  we  perceive  change,  at  least  in  many  respects, 
and  that  daily  experience  has  no  difficulty  in  ascertaining 
these  changes.  They  change,  which  means  that,  in  the  group 
of  permanent  possibilities  constituting  them,  some  particular 
possibility  perishes ;  in  other  words  again,  among  the  possi- 
ble sensations  which  denote  a  body,  some  particular  sensa- 
tion ceases  to  be  possible.  The  top  of  this  stove  was  cold  a 
short  time  ago  ;  now  the  fire  has  been  lighted,  it  is  hot.  This 
ball  of  wax  is  spherical,  hard,  odorous,  capable  of  rendering  a 
slight  sound ;  when  placed  on  the  hot  stove  it  becomes  soft, 
loses  its  sonorousness  and  smell,  and  becomes  a  thick  liquid. 
This  green  leaf  has  no  longer  any  color  in  the  dark.  I  left 
this  book  on  my  table,  and  find  it  on  one  of  the  shelves  of 
the  bookcase. — In  all  these  cases,  one  or  more  of  the  possi- 
bilities of  sensation  constituting  the  object  have  disappeared, 
but  are  replaced  or  not  by  others  of  the  same  kind. — All  these 
changes  of  bodies  are,  at  bottom,  conceived  and  conceivable 
only  with  relation  to  sensations,  since  they  are  all  reduced, 
in  final  analysis,  to  the  extinction  or  arising  of  a  possibility  of 
sensation.  But,  from  another  point  of  view,  though  bodies 
are  but  possibilities  of  sensation,  these  changes  are  none  the 
less  changes  of  bodies,  and  it  is  from  this  point  of  view  that 
we  usually  consider  them.  When  we  no  longer  find  a  sensa- 


CHAP.  I.]  EXTERNAL  PERCEPTION. 

tion  on  which  we  were  accustomed  to  reckon,  we  do  not 
ascribe  the  change  to  ourselves,  but  to  the  body ;  we  say  that 
it  has  changed  its  position,  figure,  size,  temperature,  color, 
taste,  smell,  and  though  its  history  may  be  only  definable  by 
us  through  ours,  we  confront  its  history  with  ours,  as  a  series 
of  events  opposed  to  another  series  of  events. 

On  this  two  new  series  of  properties  become  added  to  it, 
and  perfect  its  being. — On  the  one  hand  we  observe  that  it 
is  capable  of  certain  precise  changes  under  certain  precise 
conditions ;  it  may  change  place,  figure,  magnitude,  consist- 
ence, color,  smell ;  may  be  divided,  may  become  solid,  liquid, 
gaseous,  be  heated,  cooled,  etc.  We  conceive  it  with  relation 
to  its  possible  events  as  we  conceived  it  with  relation  to  our 
possible  sensations,  and,  to  the  first  group  of  possibilities  and 
permanent  necessities  by  which  we  constituted  it,  we  associ- 
ate a  second. — On  the  other  hand  we  observe  that  certain  of 
its  events  excite  certain  changes  in  other  bodies.  The  mar- 
ble in  motion  displaces  another  marble.  An  acid  solution 
reddens  litmus  paper.  The  heated  stove  evaporates  water 
placed  on  it.  A  scrap  of  heated  iron  brought  near  a  ther- 
mometer dilates  the  alcohol.  By  these  various  observations 
we  prove  that  certain  bodies  are  capable,  under  certain  precise 
conditions,  of  exciting  certain  changes  in  other  bodies,  and 
we  no  longer  define  them  by  reference  to  our  events,  nor  by 
reference  to  their  own  events,  but  by  reference  to  the  events 
of  the  other  bodies.  In  this  respect,  too,  a  body  is  still  a  group 
of  permanent  possibilities  and  necessities,  and,  with  these 
three  relationships,  we  have  completely  constituted  it. — It 
can,  and  under  certain  conditions  it  must,  excite  in  us  certain 
muscular  and  tactile  sensations  of  resistance,  extension,  figure, 
and  situation,  certain  sensations  of  temperature,  color,  sound, 
taste,  and  smell:  these  are  its  sensible  properties. — It  can,  and 
under  certain  conditions  it  must,  go  through  certain  changes 
of  consistence,  extension,  figure,  position,  temperature,  taste, 
color,  sound,  and  smell :  these  are  what  we  may  call  its  in- 
trinsic properties. — It  can,  and  under  certain  circumstances 
it  must,  excite  in  some  other  body  some  change  of  consistence 
or  extension,  or  figure,  or  position,  or  temperature,  or  of  taste, 
smell,  color,  and  sound :  these  are  its  properties  with  relation  to 


276  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

other  bodies. — All  these  properties  exist  only  with  relation  to 
events;  to  state  them  is  to  predict  some  event  of  ourselves, 
of  the  body  in  question,  of  another  body,  to  enunciate  it  as 
possible  under  certain  conditions,  as  necessary  under  the 
same  conditions  with  a  complementary  one  added  to  them, 
in  short,  to  state  a  general  law ;  and  all  these  events,  our 
own,  those  of  the  body  in  question,  those  of  the  other  bodies, 
are  defined  in  final  analysis  by  our  events. 

The  case  is  altered,  when,  from  among  this  enormous  multi- 
tude of  properties,  we  attempt  to  set  aside  fundamental  proper- 
ties. Sentient  beings  are  but  a  rank  in  the  prodigious  army  of 
distinct  beings  which  we  observe  or  divine  in  nature,  and  our 
events  are  but  a  trifling  quantity  in  the  enormous  mass  of 
events.  The  Ego  is  a  single  reagent  among  a  hundred  mil- 
lion others,  one  of  the  most  perishable,  one  of  the  most  easily 
deranged,  one  of  the  most  inaccurate,  one  of  the  most  insuffi- 
cient. In  the  place  of  its  notations  we  substitute  other  equiv- 
alent notations,  and  we  define  the  properties  of  bodies,  not 
by  our  events,  but  by  certain  of  their  events.  Instead  of  our 
feeling  of  temperature  we  take  as  guide  the  elevation  or  low- 
ering of  the  alcohol  in  the  thermometer.  Instead  of  the  mus- 
cular sensation  we  experience  in  raising  a  weight,  we  take  as 
guide  the  elevation  or  lowering  of  the  scale  of  the  balance. 
Among  these  indicating  events,  there  is  one  which  is  very  sim- 
ple and  more  universally  spread  through  nature  than  any  other 
— motion,  or  passage  from  place  to  place,  with  its  different 
degrees  of  velocity. — We  first  observe  it  in  ourselves  ;  the 
primitive  notion  we  have  of  it  is  that  of  the  more  or  less  en- 
ergetic muscular  sensations,  whose  longer  or  shorter  series  ac- 
companies the  bending  or  extension  of  our  limbs.  Just  as,  by 
analogy  and  induction,  we  attribute  to  organized  bodies,  sen- 
sations, perceptions,  emotions,  and  other  events  similar  to  our 
own,  so  we  attribute  to  all  bodies  motion  similar  to  our  own. 
But,  as  by  verification  and  rectification,  we  gradually  limit  the 
too  close  resemblance  we  at  first  imagined  between  the  in- 
ferior animals  and  ourselves,  so  we  gradually  limit  the  too 
great  resemblance  which  we  at  first  imagined  between  the 
motion  of  inanimate  bodies  and  our  own.  The  child  believed, 
and  has  ceased  to  believe,  that  its  hoop  jumped  and  ran  away, 


CHAP.  I.I  EXTERNAL   PERCEPTION.  277 

that  its  ball  ran  at  it  and  tried  to  hurt  it.  Men  imagined  and 
have  at  last  ceased  to  imagine  the  flight  of  the  projectile  as 
an  effort*  analogous  to  their  own  ;  they  have  recognized  the 
metaphor  for  a  metaphor,  and  have  reduced  it  so  that  it  may 
correspond  with  a  body  incapable  of  intention  and  sensation. 
Instead  of  conceiving  motion  as  a  series  of  successive  sensa- 
tions interposed  between  the  moments  of  departure  and  ar- 
rival, he  now  conceives  it  as  a  series  of  successive  states  inter- 
posed between  the  moments  of  departure  and  arrival ;  by  this 
retrenchment,  the  kind  and  quality  of  the  elements  which 
compose  the  series  are  omitted ;  nothing  remains  but  their 
number  and  order,  and  the  notion  is  applicable,  not  merely 
to  sentient  bodies,  but  to  all  bodies. 

This  being  settled,  he  gradually  discovers  that,  in  his 
definitions  of  bodies  and  their  properties,  a  mode  or  par- 
ticularity of  motion  so  conceived  may  take  the  place  of  his 
sensations.  He  called  that  solid  which  excited; in  him  the 
sensation  of  resistance  ;  he  now  calls  solid  whatever  arrests 
the  progress  of  any  body  in  motion.  He  conceived  empty 
space  by  his  muscular  sensations  of  free  locomotion  ;  he  now 
conceives  it  by  the  unarrested  motion  of  any  body  whatever. 
He  represented  lines,  surfaces,  and  solids  by  more  and  more 
complex  groups  of  which  his  sensations  of  locomotion,  con- 
tact, and  resistance  formed  the  elements  ;  he  now  defines  the 
line  by  the  motion  of  a  point ;  the  surface  by  the  motion  of 
a  line  ;  the  solid  by  the  motion  of  a  surface.  He  estimated 
force  by  the  magnitude  of  his  -sensation  of  effort;  he; now 
measures  it  by  the  velocity  of  the  motion  it  impresses  on  a 
given  mass,  or  by  the  magnitude  of  the  mass  on  which  it 
impresses  a  motion  of  a  given  velocity. — He  thus  attains  the 
conception  of  body  as  a  movable  motor,  of  which  velocity  and 
mass  are  equivalent  aspects.  Thus,  all  the  events  of-physi- 
cal  nature  are  motions,  each  of  them  being  defined  by  the 
mass  and  velocity  of  the  body  in  motion ;  and  each  being  a 
quantity  which  passes  from  body  to  body  without  ever  in- 
creasing or  diminishing.  Such  is  at  present  the  mechanical 
idea  of  nature.  Among  the  various  classes  of  events  by 

*  Nisus. 


THE  KNOWLEDGE    OF  BODIES.  [BOOK  II. 

which  we  can  define  things,  man  chooses  one,  refers  to  it  the 
majority  of  the  others,  and  imagines  that  some  day  he  will 
be  able  so  to  refer  the  rest.  But  if  we  analyze  the  one  he 
has  chosen,  we  discover  that  all  the  original  and  constituting 
elements  of  his  definition  are,  like  the  definitions  of  all  the 
rest,  nothing  more  than  sensations,  or  more  or  less  elaborated 
extracts  from  sensations. 

VII.  Among  these  extracts  from  sensation  by  which,  in 
final  analysis,  we  invariably  conceive  and  define  bodies,  is 
there  any  one  which  we  may  legitimately  attribute  to  them  ? 
Or  are  bodies,  indeed,  nothing  more  than  a  simple  collection 
of  permanent  powers  or  possibilities,  of  which  we  can  affirm 
nothing  except  the  effects  they  excite  in  us?  Or,  indeed,  as 
Bain  and  Mill,  following  Berkeley,  think,  are  they  pure  non- 
entity, erected  by  an  illusion  of  the  human  mind  into  sub- 
stances and  external  things  ?  Is  there  nothing  more  in  nature 
than  series  of  transient  sensations  which  constitute  sentient 
subjects,  and  the  durable  possibilities  of  these  same  sensa- 
tions ?  Is  there  nothing  intrinsic  in  this  stone  ?  Do  we 
only  discover  in  it  relative  properties,  for  instance,  the  pos- 
sibility of  certain  tactile  sensations  for  a  sentient  subject,  the 
necessity  of  these  same  tactile  sensations  for  the  sentient 
subject  who  will  give  himself  a  certain  series  of  muscular  sen- 
sations, that  is  to  say  the  series  of  muscular  sensations  in 
consequence  of  which  his  hand  will  arrive  at  touching  the 
stone  ? — We  have  already  seen  that  what  constitutes  a  dis- 
tinct being,  is  a  distinct  series  of  facts  or  events.  Consequently, 
in  order  that  this  stone  maybe,  not  the  simple  permanent  pos- 
sibility of  certain  sensations  of  a  sentient  subject,  a  vain  and  in- 
effectual possibility  in  case  all  sentient  subjects  were  sup- 
pressed, it  is  necessary  that  it  should  be,  in  addition,  a  distinct 
series  of  facts,  or  of  real  or  possible  events — events  which  would 
still  be  produced  in  the  absence  of  all  sentient  beings.  May 
we  by  induction  and  analogy  attribute  to  it  such  a  series? — All 
followers  of  Berkeley  are  agreed  that  we  may  legitimately  do 
so  by  induction  and  analogy,  when,  instead  of  a  stone,  we  are 
dealing  with  a  sentient  subject,  man  or  animal,  other  than 
ourselves.  In  this  case  not  only  do  we  conceive  the  object 
perceived  by  our  senses  as  a  collection  of  permanent  possi- 


CHAP.  I.]  EXTERNAL  PERCEPTION.  279 

bilities,  but  more  than  this,  we  rightly  attribute  to  It  a  series 
of  sensations,  images,  and  ideas,  more  or  less  analogous  to 
our  own,  and  we  legitimately  transfer  to  it  events  which  pass 
in  us.  By  this  transfer,  instead  of  the  simple  possibility 
which  it  was,  it  becomes  an  actual  thing  in  the  same  way  as 
ourselves,  and  we  recognize  in  it  a  distinct  existence,  inde- 
pendent of  ours,  since  the  events  which  constitute  it,  though 
proved  by  us,  have  no  need  of  our  events  for  their  production 
and  succession. 

Is  there  any  series  of  internal  events  which  we  may,  still 
by  induction  and  analogy,  transfer  from  ourselves  to  the  stone, 
in  order  to  confer  on  the  stone  the  independent  and  distinct 
existence  which  we  have  conferred  on  the  being  similar  to 
ourselves  or  on  the  animal? — Yes,  certainly,  at  least    in  my 
opinion,  and  by  means  of  preliminary  eliminations.     As  we 
have  seen  just  now,  from  the  series  of  muscular  sensations 
by  which  we  conceive  motion,  we  cut  away  all  the  characters 
which    can    distinguish   it  from  another  series.      After  this 
great  suppression,  it  is  nothing  more  for  us  than  an  abstract 
series  of  successive  states,  interposed  between  a  certain  initial 
moment  and  a  certain  final  moment.      Each  of  these  com- 
ponent states  has  been  stripped  of  all  qualities,  and  is  defined 
only  by  it  position,  in  the  series,  as  being  nearer  or  more  dis- 
tant from  the  initial  or  the  final  moment.     It  is  this  series 
more   or   less   short,  of  successive  states  comprised  between 
an  initial  moment  and  a  final  moment,  and  defined  only  by 
their  reciprocal  order,  that  we  term  pure  motion. — Now,  we 
have  all  the  reasons  in  the  world  to  attribute  this  to  the  r~ 
known  things  we  term  bodies,  to  be  certain  that   i4" 
from  one  to  another  of  them,  and  to  lay  down   tl 
such  communication.     In  fact,  if  all  sentient  being 
pressed,  our  stone  would  still  subsist ;  and  this  does 
mean  that  the  possibility  of  certain  visual,  tactile,  aim  orner 
sensations  would  still  subsist ;  it  also  means  that  the  unknown 
things   we   term   molecules,  and  which  make  up  the  stone, 
would  still  subsist ;  in  other  words  that  the  movable  motive 
powers  of  which  the  stone  is  the  aggregate  would  continue 
to  weigh  on  the  ground  proportionately  to  their  mass,  and 
would  go  through  the  same  internal  oscillations  as  they  do  at 


28o  THE   KNOWLEDGE   OF  BODIES.  [BOOK  II. 

present.  Whatever  be  the  being,  animate  or  inanimate,  we 
may  consider  it  in  two  aspects,  with  relation  to  others,  and 
in  itself. — In  relation  to  others,  it  is  a  condition  of  events  for 
the  others,  and,  especially  with  relation  to  us,  it  is  a  condition 
of  sensations  for  us  ;  in  this  respect  it  is  determined,  but  solely 
with  relation  to  us,  and  we  can  say  nothing  more  of  it  than 
that  it  is  the  permanent  possibility  of  certain  sensations  for 
us. — On  the  other  hand,  in  itself,  it  is  a  series  of  events  which, 
in  certain  conditions,  tend  to  be  accomplished  ;  in  this  respect 
it  is  determinate  in  itself,  and  we  may  say  of  it  that  it  is  this 
series  conjoined  to  the  tendencies  by  which  it  is  accomplished. 
—This  man  is,  first,  the  permanent  possibility  of  tactual,  vis- 
ual, and  other  sensations,  which  I  experience  in  his  neighbor- 
hood ;  and  further,  he  is  a  distinct  series  of  sensations,  images, 
ideas,  and  volitions,  conjoined  to  the  tendencies  by  which 
this  series  is  accomplished.  So,  too,  this  stone  is,  first,  the 
permanent  possibility  of  visual,  tactile,  and  other  sensations, 
which  I  experience  in  its  neighborhood  ;  and  further,  it  is  a 
distinct  group  of  tendencies  to  motion,  and  of  distinct  motions 
in  way  of  being  accomplished. 

No  doubt,  we  know  nothing  of  animate  or  inanimate  beings 
except  from  the  sensations  they  give  us.     No  doubt,  too,  the 
various  materials  with  which  we  internally  construct  their  idea 
are  our  sensations,  or  more  or  less  elaborated  extracts  from 
our  sensations.     But  we  may,  upon  authentic  evidence,  refer 
to  things  external,  some  of  these  more  or  less  transformed 
and  reduced  materials,  and  attribute  to  such  things  a  distinct 
"xistence  without  us,  analogous  to  that  which  they  have  within 
ve  are  naturally  inclined  by  imagination  and  sympathy 
Deration.      At  the  sight  of  a  rocket  fired  off,  just  as 
«.t  of  a  flying  bird,  we  involuntarily  put  ourselves 
j  of  the  object ;  we  mentally  repeat  its  flight ;  we 
mutate  it  by  our  attitude  and  gestures.     Infant  nations,  in 
whom  this  aptitude  is  intact,  carry  it  out  to  far  greater  ex- 
tents than  we  do.     The  primitive  man,  Aryan  or  Greek,  bes- 
towed his  soul  upon  fountains,  rivers,  mountains,  clouds,  the 
air,  upon  all  the  aspects  of  the  heavens  and  the  day ;  he  saw 
in  inanimate  things,  living  beings  similar  to  himself.     Gradu- 
ally, by  means  of  experiences  and  verifications,  we  have  re- 


CHAP.  I.]  EXTERNAL  PERCEPTION.  28l 

strained  this  too  complete  transference  of  ourselves  to  exter- 
nal things.  At  present,  we  have  reduced  it  to  a  minimum ; 
we  have  suppressed  even  the  last  vestiges  of  the  primitive 
error ;  we  no  longer  attribute  to  inanimate  things,  attrac- 
tions, repulsions  and  efforts,  conceived  on  the  model  of  our 
mental  states  denoted  by  these  words ;  when  we  use  such 
language,  we  know  that  it  is  merely  by  approximation  and 
metaphor.  If  we  attribute  motion  to  bodies,  it  is  after  strip- 
ping its  elements  of  all  human  qualities,  after  taking  from 
them  all  the  characters  by  which  they  were  at  first  sensations, 
by  carefully  leaving  nothing  of  them  but  their  relative  order, 
their  position  in  relation  to  the  inital  and  final  moment,  their 
more  or  less  speedy  succession  in  the  same  interval  of  time. 
In  this  state  of  extreme  attenuation  and  curtailment,  the  con- 
tinuous series  of  successive  events  constituting  the  motion  of 
a  stone  we  throw,  is  nothing  more  than  a  very  slight  extract, 
the  slightest  possible  extract,  of  that  continuous  series  of 
successive  muscular  sensations  first  constituting  to  us  the 
motion  of  our  hand.  But  we  may  justly  attribute  such  a  series 
to  the  stone,  and  in  this  respect,  it  is  to  us  a  being  as  real, 
as  complete,  as  distinct  from  us,  as  any  particular  man  or 
horse.* 


*  By  this  addition  to  the  theory  of  Bain  and  Mill,  we  restore  to  bodies  an  actual 
existence,  independent  of  our  sensations.  But  the  theory,  with  the  aid  of  this  ad- 
dition, leads  us  much  further,  and  enables  us  to  complete  the  views  we  have  al- 
ready presented  upon  the  relations  of  physical  and  mental  events.  (See  part  i. 
book  iv.  ch.  ii.  p.  200.) 

It  follows,  from  the  analysis  of  motion,  that  it  is  not  absolutely  heterogeneous 
to  sensation  :  for  our  idea  of  it  is  formed  from  the  materials  supplied  by  our  mus- 
cular sensations  of  locomotion.  In  the  series  of  successive  muscular  sensations 
which  make  up  a  whole  sensation  of  locomotion,  strip  the  component  sensations 
of  all  intrinsic  quality  and  difference  ;  consider  them  abstractedly,  as  pure  succes- 
sive events,  determined  solely  by  their  relative  order  in  the  series,  and  by  the  whole 
time  they  take  to  succeed  one  another  in  this  order  from  the  initial  to  the  final 
moment  ;  it  is  this  abstract  series  which  constitutes  to  us  the  movements  of  our 
arm,  and  which  we  attribute  by  induction  and  analogy  to  the  stone  our  hand  carries 
with  it. — Now,  the  elements  of  this  abstract  series  being  thus  brought  down  to  the 
maximum  degree  of  possible  simplicity,  maybe  considered  as  elementary  sensation  at 
their  maximum  of  possible  simplicity.  In  such  a  case  the  most  simple  motion, 
such  as  we  attribute  to  a  movable  point,  would  be  precisely  the  most  simple  series 
of  those  elementary  mental  events,  whose  degraded  forms  we  have  seen  extending, 
while  becoming  still  more  degraded,  under  the  compound  mental  events,  sensations, 


282  THE  KNOWLEDGE   OF  BODIES.  [Boux  II. 

VIII.  We  now  know  the  materials  by  whose  assemblage 
the  conception  of  a  body  is  formed.  All  these  materials  are 
images  of  sensations,  possible  under  certain  conditions,  and 
necessary,  under  the  same  conditions,  with  a  complementary 
one  added.  When  nothing  contradicts  this  conception,  and 
when,  instead  of  being  repressed  and  negative,  it  is  excited  and 
sustained  by  the  actual  sensation,  it  is  affirmative  and  becomes 
a  judgment.  Therefore,  we  now  see  the  part  it  plays  in  an 
external  perception.  I  lay  my  hand  in  the  dark  on  this  mar- 
ble table,  and  I  have  an  actual  sensation  of  contact,  of  resist- 
ance, and  of  cold.  Upon  this  sensation,  images  arise  of  many 
distinct  and  interconnected  sensations,  that  of  the  precisely 
similar  sensations  of  contact,  resistance,  and  cold,  which  I 
should  experience  if  I  repeated  the  trial,  that  of  the  nearly 
similar  sensations  of  contact,  resistance,  and  cold,  which  I 
should  experience  if  I  placed  my  hand  beyond  the  spot  I 
touched,  that  of  the  muscular  sensations  of  locomotion,  dur- 


and  images,  of  which  we  are  conscious.  Sensations  and  images  would  thus  be 
but  more  complex  cases  of  motion. — By  this  reduction,  the  two  idioms,  of  con- 
sciousness and  of  sense,  by  which  we  read  the  great  book  of  Nature,  would  be  re- 
duced to  a  single  one  ;  the  mutilated  text  and  the  mutilated  interlinear  translation 
which  mutually  supply  one  another  would  be  one  and  the  same  tongue,  written  in 
different  characters,  with  more  complex  characters  in  the  supposed  text,  with  more 
simple  characters  in  the  supposed  translation,  and  the  link  connecting  the  trans- 
lation and  the  text  would  be  found  in  the  relation  discovered  between  our  idea  of 
motion  and  the  muscular  sensation  of  locomotion  which  supplies  the  elements  of 
this  idea. 

If  this  be  admitted,  we  are  enabled  to  include  nature  in  a  general  glance. 
The  simultaneous  series  of  successive  events  composing  it  would  be  all  homogene- 
ous. Their  type  would  be  furnished  us  by  the  sensation  as  we  observe  it  in  our- 
selves, and  in  the  elementary  sensations,  more  and  more  degraded  and  simplified, 
of  which  this  whole  sensation  is  made  up.  At  tlie  extreme  limit  of  simplicity  all 
would  be  reduced  to  motions,  which  would  themselves  be  nothing  more  than  con- 
tinuous series  of  infinitesimal  sensations,  stripped  of  all  quality,  and  definable  only 
in  respect  of  quantity,  that  is  to  say  by  the  duration  employed  in  their  accomplish- 
ment, and  by  the  magnitude  of  the  succeeding  effect.  In  this  respect,  all  the  facts 
and  events  of  nature  might  be  reduced  to  motions,  and  our  sciences,  all  of  which 
have  for  their  object  the  discovery  of  simple  elements,  might  all  be  reduced,  as  in- 
deed all  tend  to  be  reduced,  to  mechanics. — But  this  would  be  so,  from  the  analyt- 
ical aspect  only.  Motion  itself  would  be  conceivable  only  by  the  series  of  muscu- 
lar sensations  of  which  it  is  the  most  slender  extract,  and,  directly,  the  type  of  ex- 
istence would  be  the  mental  event,  sensation,  or  image,  just  as  consciousness  pre- 
sents it  to  us. 


CHAP.  I.]  EXTERNAL  PERCEPTION.  283 

ing  which  these  tactile  sensations  would  be  received,  and  at 
whose  expiration  they  would  be  no  longer  received,  that  of 
the  visual  sensations  of  color  and  form,  which  would  arise  in 
me  if  there  were  light  and  my  eyes  were  open,  etc.  I  further 
believe  that,  by  placing  myself  under  the  required  conditions, 
not  only  might  I  experience  the  sensations  in  question  at 
any  moment  of  the  future,  but,  moreover,  that  I  might  have 
experienced  them  at  any  moment  of  the  past,  and  that  the 
same  would  happen  at  any  moment  of  the  present,  past, 
or  future,  with  every  being  analogous  to  myself. 

In  this  group  of  images  called  up  by  the  sensation,  two 
things  must  be  distinguished,  the  images  themselves,  and  the 
reflection  by  which  I  remark  the  permanent  possibility,  at  all 
times  and  for  every  sensibile  being,  of  the  sensations  which 
they  represent.  The  first  of  these  two  things  is  animal,  the 
second  is  human. — In  fact,  animal  experience  is  sufficient  to 
attach  the  group  of  images  to  the  sensation ;  we  have  seen 
the  laws  of  revival  and  association  which  form  and  arouse  it. 
When  a  dog  touches  the  table,  all  the  images  we  have  enu- 
merated arise  in  him  as  in  us ;  consequently  he  can  foresee, 
as  we  do,  that  if  he  runs  against  the  table  he  will  be  bruised, 
that  if  he  lies  down  on  it  he  will  feel  cold,  that  if  he  opens 
his  eyes  to  look  at  it  he  will  have  a  certain  visual  sensation. 
This  is  sufficient  to  enable  him  to  avoid  danger,  to  provide 
for  his  wants,  to  direct  his  proceedings.  If  he  sees,  smells,  or 
touches  a  piece  of  meat,  he  has,  by  revival  and  association, 
the  image  of  a  sensation  of  pleasant  taste,  and  this  image  in- 
duces him  to  snap  it  up.  When  he  sees  a  lifted  stick  or  hears 
the  crack  of  a  whip,  he  has,  by  revival  and  association,  the 
image  of  a  painful  sensation  of  touch,  and  this  image  induces 
him  to  run  away.  In  his  case  there  is  nothing  more  ;  he  is 
not  possessed  of  language,  he  has  not  the  means  of  discerning 
and  isolating  the  characters  of  his  image. — We  have  these 
means,  and  avail  ourselves  of  them.  The  child  learns  the 
words  table,  stick,  meat,  stone,  tree,  and  others ;  they  gradual- 
ly become  equivalent  for  him  to  the  group  of  animal  images 
which  first  constituted  his  whole  perception.  He  incessantly 
avails  himself  of  them  ;  when  grown  up,  he  enquires  into 
their  meanings  and  couples  them.  The  man  then  observes 


284  THE    KNOWLEDGE   OF  BODIES.  [BOOK  II. 

that  the  sensation  of  which  he  has  the  image  was  possible 
just  before,  that  same  morning,  the  day  before,  that  it  will 
be  possible  presently,  this  evening,  to-morrow,  and  at  every 
intervening  moment,  and  not  only  for  him,  but  for  evey  be- 
ing analogous  to  himself.  He  notes  this  possibility;  he  dis- 
engages it  from  the  sensations  in  which  it  is  included  ;  he  is 
struck  by  the  singularity  of  its  independence  and  permanence 
in  the  midst  of  the  continuous  flow  and  manifest  dependence 
of  the  sensations.  He  denotes  it  by  the  words  property, 
power,  force.  As  it  is  independent  and  permanent,  it  seems 
to  him  alone  worthy  of  attention,  and  henceforth,  to  fill  the. 
scene  of  being,  he  puts  it  into  the  first  rank  with  other  simi- 
lar Possibilities. — He  correspondingly  discards  or  lays  aside 
as  of  small  importance  fugitive  sensations,  and,  owing  to  their 
omission,  forgets  that  properties,  powers  and  forces  are  but 
extracts  from  them.  He  attempts  to  consider,  apart  and  in 
itself,  this  permanent  and  independent  thing  which  he  has  only 
isolated  by  an  oversight.  Thus,  he  creates  an  empty  sub- 
stance ;  metaphysics  sets  to  work  and  builds  her  card-castles 
upon  this  entity ;  in  order  to  upset  them  the  most  rigorous 
analysis  is  hardly  sufficient. — There  remains,  then,  to  consti- 
tute the  perception  of  a  body,  first,  an  actual  sensation  and 
an  associated  group  of  images,  next,  the  conception,  that  is 
to  say  the  extraction  and  notation  by  means  of  a  sign,  of  a 
character  common  to  all  the  sensations  represented  by  these 
images,  a  permanent  character  which,  when  interpreted  by 
metaphysical  illusion,  becomes  isolated  and  appears  a  separate 
being.  Sensations  and  images,  these  form  the  crude  and 
primitive  materials  ;  gradual  and  superadded  abstraction  com- 
pletes the  edifice. — Here  we  have  the  first  foundation  of  the 
hallucinatory  semblance  which  arises  in  us,  when,  upon  a  sen- 
sation, we  conceive  and  affirm  an  extended,  resisting,  mova- 
ble substance,  localized,  and  possessed  of  other  sensible  prop- 
erties. The  operation  which  completes  it  and  opposes  it  to 
ourselves,  by  casting  it  into  the  distance  and  situating  it  with- 
out us,  remains  to  be  described. 


CHAP.  II.]          THE  EDUCATION  OF   THE   SENSES.  285 


CHAPTER    II. 

EXTERNAL  PERCEPTION  AND  THE  EDUCATION  OF  THE  SENSES. 

I.  ALONG  with  the  great  mental  process  of  which  we  have 
been  speaking,  another  is  accomplished,  as  involuntary,  as  si- 
lent, and  as  fruitful  in  illusions  and  cognitions.  Every  special 
sensation  becomes  transformed,  and  acquires  an  apparent  posi- 
tion. We  never  now  experience  a  sensation  without  assign- 
ing it  a  place.  As  soon  as  we  have  an  impression  of  cold,  of 
heat,  of  pain,  of  contact,  of  muscular  contraction,  of  taste,  of 
smell,  we  can  point  out  more  or  less  precisely  the  spot  at  which 
we  feel  it,  as — in  the  hand,  the  cheek,  the  middle  of  the  arm, 
the  nose,  the  tongue. — There  is  no  appreciable  interval  be- 
tween this  judgment  and  the  sensation  itself;  we  are  even 
tempted  to  believe  that  the  two  events  are  one,  and  that  we 
observe,  at  the  same  moment,  the  twitch  of  pain  and  its  lo- 
cality. There  is,  though,  an  interval  between  these  two  ob- 
servations, and  the  delicate  processes  employed  by  physiolo- 
gists have  recently  succeeded  in  measuring  it  ;*  the  fact  is 
that  the  operation  by  which  we  localize  our  sensation  in  a 
particular  spot  of  one  of  our  limbs  is  a  subsequent  and  more 
or  less  complex  addition,  whose  more  or  less  numerous  mo- 
ments require  for  their  succession  a  longer  or  shorter  time.f 


*  Experiments  of  Helmholtz,  Marey,  De  Bezold,  Hirsch,  Van  Deen,  Donders, 
De  Jaager,  Wolf.  Collected  and  summed  up  by  M.  Radau,  in  the  "  Revue  des 
Deux  Mondes,"  I  Aug.  1867,  p.  794. 

f  M.  de  Jaager  told  the  person  on  whom  he  was  experimenting  to  touch  the 
key  of  the  electric  machine  with  his  left  hand,  when  he  received  the  shock  on  his 
right  side,  and  with  his  right  hand  when  he  received  the  shock  on  his  left  side. 
Thus,  two  cases  were  presented.  Sometimes  the  person  was  told  beforehand  that 
the  shock  would  be  received  on  a  particular  side,  the  right,  for  instance  ;  in  this 
case,  the  interval  between  the  shock  he  received  and  the  consecutive  signal  he  gave 
amounted  to  '2  of  a  second.  Sometimes  he  was  not  told  on  what  side  he  would 


286  THE  KNOWLEDGE   OF  BODIES.  [BooK  II. 

—By  this  localizing  operation  our  sensation  receives  a  false 
appearance,  arid  this  appearance  begets  others,  which  are,  in 
themselves,  illusions,  but  which,  by  their  correspondence  with 
things,  constitute  the  perfectionment  or  education  of  the 
senses. — When  once  the  sensation  has  arrived  at  this  state, 
the  bodies  it  reveals  to  us  correspondingly  receive  new  char- 
acters ;  the  hallucinatory  semblance  which  constitutes  exter- 
nal perception  is  completed ;  and  the  object,  which  appeared 
only  as  something  permanent  and  fixed,  now  appears  as  some- 
thing beyond  us  and  without  us. 

II.  I  put  my  foot  to  the  ground  ;  I  experience  a  sensation 
of  pressure,  and  determine  that  it  is  situated  in  my  left  foot, 
that  it  is  strong  in  the  middle  of  the  foot,  light  at  the  heel, 
scarcely  perceptible  at  the  toes.  Let  us  consider  this  conclu- 
sion ;  taken  in  itself,  it  is  false  ;  the  sensation  is  not  in  my 
foot.  In  this  case,  physiologists  long  ago  detected  the  error 
and  established  the  theory.  The  truth  is  that  a  disturbance 
is  produced  in  the\  nerves  of  the  foot,  of  greater  extent  in  the 


receive  the  shock,  and  the  shock  came,  for  instance,  from  the  right ;  in  this  case 
the  interval  between  the  shock  he  received  and  the  consecutive  signal  he  gave 
amounted  to  "2.1  of  a  second.  The  difference,  then,  between  the  two  cases  amount- 
ed to  '07  of  a  second. — It  is  clear  that  in  each  case  the  crude  sensation  was  produ- 
ced at  the  same  instant ;  but,  in  the  first  case  the  image  of  the  shock  on  the  right 
was  fully  prepared  to  enter  on  the  scene,  and  was  not  counterbalanced,  as  in  the 
second  case,  by  the  equal  readiness  of  the  image  of  the  shock  on  the  left.  To  up- 
set this  equilibrium,  and  to  permit  the  image  of  the  shock  on  the  right  to  attach 
itself  by  selection  to  the  supervening  sensation,  required  a  certain  time,  and  by  the 
experiment  the  time  required  is  '07  of  a  second. — In  general,  between  a  sensation 
and  a  consecutive  signal  there  elapses  two-tenths  of  a  second,  and,  if  the  sensation, 
that  of  a  momentary  sound,  of  an  electric  shock,  of  a  spark,  requires  to  call  up  an 
auxiliary  image,  it  employs,  when  this  image  is  not  in  readiness  or  is  counterbal- 
anced by  another,  one-tenth  of  a  second  longer  than  when  this  auxiliary  image  is 
in  readiness,  or  has  no  antagonist. — Images,  then,  require  an  interval  of  time  to 
connect  themselves  to  the  sensation,  and  this  interval  is  increased  when  their  call- 
ing up  is  less  prepared  or  more  disputed. 

MM.  Bonders  and  De  Jaager  made  the  experiment  in  a  slightly  different  man- 
ner. One  of  them  pronounced  a  syllable,  the  other  repeated  it  as  soon  as  he  heard 
it ;  the  vibrations  of  the  word  were  registered  by  a  phonautograph  ;  when  the  re- 
peated syllable  had  been  agreed  on  beforehand,  the  difference  observed  was  two- 
tenths  of  a  second  ;  in  the  other  case,  it  was  three-tenths. — Analogous  results  were 
obtained  by  an  observer  noting  the  appearance  of  a  white  or  red  light,  and  being, 
in  turn,  informed  and  not  informed  which  would  be  shown. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  28/ 

sole,  and  of  less  at  the  toes  and  heel,  that  this  disturbance  is 
communicated  throughout  the  whole  course  of  the  nerves  to 
the  sensory  centres  of  the  encephalon,  and  that  the  sensation 
really  takes  place  in  the  encephalon.  We  are  mistaken  in 
situating  it  in  the  periphery  of  the  nervous  system,  it  is  at 
the  centre  ;  what  is  produced  in  the  foot  is  not  the  sensation, 
but  the  commencement  of  the  nervous  disturbance  of  which 
the  sensation  is  the  final  result. 

There  are  superabundant  proofs  of  this.  They  may  be 
all  summed  up  by  saying  that,  in  many  instances,  the  sensa- 
tion appears  situated  in  a  place  where  it  certainly  is  not.  By 
means  of  these  instances  we  prove  a  general  law  :  that,  in  our 
present  state,  as  soon  as  a  sensation  arises,  it  is  accompanied 
by  a  judgment  in  which  we  pronounce  it  to  be  situated  in 
some  particular  spot.  It  may  be  that,  in  such  a  case,  there 
actually  is  a  nervous  disturbance  at  this  spot,  or,  it  may  be, 
that  there  is  no  such  disturbance  there.  It  matters  little ; 
the  judgment  takes  place  in  the  second  case  as  well  as  in  the 
first,  the  sensation,  by  itself,  is  sufficient  to  give  rise  to  the 
judgment,  and  acquires  through  the  judgment  an  apparent 
situation.  The  situation,  then,  was  acquired  in  the  first  case, 
when  nervous  disturbance  was  existing  at  the  indicated  spot, 
just  as  in  the  second  case,  in  which  no  nervous  disturbance 
was  existing  there.  When  once  it  is  established,  in  accord- 
ance with  the  second  case,  that  a  certain  position  attributed 
to  a  certain  sensation  is  apparent  only,  it  invincibly  follows 
that,  in  the  first  case,  the  same  position  attributed  to  the  same 
sensation  is  also  apparent  only.  If,  then,  in  the  first  case, 
we  find  anything  at  all  at  the  indicated  spot,  it  is  not  the  sen- 
sation, but  one  of  its  antecedents  or  consequents,  an  event 
connected  with  it,  and  which  it  denotes,  a  real  event,  no  doubt, 
but  other  than  the  sensation,  and  which,  by  a  happy  correspon- 
dence, usually  accompanies  the  sensation  in  the  normal  state. 

Let  us  now  consider  the  cases  by  which  we  are  undeceived. 
There  is,  first,  a  class  already  mentioned,  that  of  persons  who 
have  lost  limbs.  "  It  is  a  fact,"  says  Mueller,  "  known  to  all 
surgeons,  and  subject  to  no  exception,  that  when  a  limb  has 
been  removed  by  amputation,  the  remaining  portion  of  the 
nerve  which  ramified  in  it  may  still  be  the  seat  of  sensations, 


288  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

which  are  referred  to  the  lost  part.  It  is  usually  said  that 
the  illusion  continues  for  some  time,  namely,  as  long  as  the 
patient  is  under  the  care  of  the  surgeon ;  but  the  truth  is, 
that  in  most  cases  it  persists  throughout  life  :  of  this  it  is  easy 
to  convince  oneself  by  questioning  a  person  whose  limb  has 
been  amputated,  at  any  period  after  the  operation.  The  sen- 
sations are  most  vivid  while  the  surface  of  the  stump  and  the 
divided  nerves  are  the  seat  of  inflammation,  and  the  patient 
then  complains  of  severe  pain  felt  as  if  in  the  whole  limb  which 
has  been  removed.  When  the  stump  is  healed,  the  sensa- 
tions which  we  are  accustomed  to  have  in  a  sound  limb,  are 
still  felt  ;  and  frequently  throughout  life  there  is  a  tingling, 
and  often  pain,  felt,  which  are  referred  to  the  parts  that  are 
lost.  These  sensations  are  not  of  an  undefined  character  ; 
the  pain  and  tingling  are  distinctly  referred  to  single  toes,  to 
the  sole  of  the  foot,  to  the  dorsum  of  the  foot,  to  the  skin, 

&c I    have    convinced    myself  of  the    constancy   of 

these  sensations — of  their  continuance  throughout  life — al- 
though patients  become  so  accustomed  to  them  as  to 

cease  to  remark  them A  man  whose  thigh  had  been 

amputated,  still  had,  after  the  expiration  of  twelve  years, 
feelings  which  seemed  to  be  in  the  toes  and  sole  of  the  lost 

foot,  and  occasionally  severe  pains  referable  to  the  sole 

I  applied  a  tourniquet  to  the  stump,  so  as  to  press  upon  the  is- 
chiatic  nerve ;  and  he  immediately  said  that  he  felt  his  leg  asleep, 

and  a  very  distinct  tingling  in  the  toes Another,  who 

had  his  arm  amputated  above  the  elbow,  thirteen  years  ago, 
has  never  ceased  to  have  sensations  as  if  in  the  fingers.  He 
imagines  that  he  feels  the  hand  in  a  bent  position.  He  feels 
a  pricking  in  the  fingers,  particularly  when  he  lies  upon  the 
stump,  so  as  to  press  the  brachial  nerves.  I  applied  pressure 
to  the  nerves  in  the  stump ;  and  he  immediately  felt  the  whole 

arm,  even  the  fingers,  as  if  asleep Another,  whose 

right  arm  had  been  shattered  by  a  cannon-ball  in  battle, 
above  the  elbow,  twenty  years  ago,  and  afterwards  amputa- 
ted, had  still,  at  changes  of  the  weather,  distinct  rheumatic 
pains,  which  seemed  to  him  to  exist  in  the  whole  arm ;  and 
though  removed  so  long  ago,  the  lost  part  was,  at  those  times, 
felt  as  if  sensible  to  draughts  of  air.  This  man  also  com- 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  289 

pletely  confirmed  our  statement,  that  the  sense  of  the  integ- 
rity of  the  limb  is  never  lost."  * — These  illusions  are  strongest 
at  night ;  the  patients  are  sometimes  then  compelled  to  put 
their  hands  to  the  spot  where  their  limb  ought  to  be,  to  con- 
vince themselves  of  its  absence.  When  the  subsisting  por- 
tions of  the  nerves  become  painful,  they  have  still  more  diffi- 
culty in  rectifying  their  error ;  one  man,  after  eight  months 
had  elapsed,  could  only  undeceive  himself  by  feeling  at  night 
and  looking  by  day  at  the  empty  place  left  by  the  amputation 
of  his  left  arm. — It  is  plain  that  in  all  these  cases  the  sensa- 
tion of  twinging,  of  the  limb  being  asleep,  of  tingling,  of  pain, 
is  not  situated  in  the  absent  limb,  therefore  the  same  sen'sa- 
tion  is  not  situated  in  the  limb,  when  the  limb  is  there  ;  thus, 
in  the  two  cases,  in  the  normal  and  the  abnormal  state,  the 
sensation  has  not  the  situation  we  attribute  to  it ;  it  is  else- 
where ;  it  is  not  the  sensation,  but  a  nervous  disturbance 
which,  in  the  normal  state,  occupies  the  place  at  which  the 
sensation  seems  to  be.  The  nerve  is  a  simple  conductor; 
from  whatever  point  its  disturbance  may  start  on  its  way  to 
arouse  the  action  of  the  sensory  centres,  the  same  sensation 
is  produced,  and  involves  the  play  of  the  same  internal  mech- 
anism, that  is  to  say,  the  attribution  of  the  sensation  to  some 
spot  other  than  the  sensory  centre. 

Numbers  of  facts  are  explicable  by  this  observation  :  a 
violent  blow  on  the  cubital  nerve  excites  a  pain  which  ap- 
pears to  be  situated  through  all  the  ulterior  course  of  the 
nerve,  especially  at  the  back  and  palm  of  the  hand,  in  the 
fourth  and  fifth  fingers. — The  same  thing  happens,  if  the 
elbow  be  plunged  into  a  mixture  of  water  and  pounded 
ice. — Again,  when  the  cubital  or  sciatic  nerve  is  compressed, 
the  feeling  of  pricking  or  of  being  asleep  seems  to  be  ex- 
perienced by  the  internal  parts  of  the  limb.  "  In  .an  ampu- 
tation," says  Mueller,!  "  at  the  moment  of  the  division  of 
the  nerves,  the  most  violent  pains  are  felt,  as  if  in  the  part 
which  is  being  amputated,  and  to  which  the  divided  nerves 
are  distributed.  The  experienced  surgeon  of  the  Hamburg 


*  Mueller,  "  Physiology  "  (tr.  Baly),  i.  694,  695,  «. 
f  Mueller,  op.  cit.  (tr.  Baly),  i.  691. 
19 


290  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

hospital,  Dr.  Fricke,  assures  me  that  this  is  a  constant  phe- 
nomenon."— For  the  same  reason,  disease  of  the  nervous 
trunk,  or  of  the  marrow,  excites  pains  or  tinglings  which 
the  patient  believes  to  be  situated  in  the  healthy  extremities 
of  his  limbs. — So,  too,  certain  paralyzed  persons,  whose  exter- 
nal parts  are  wholly  insensible  to  pricking  and  burning,  still 
feel  in  them  pains  and  twitchings. — Lastly,  take  the  cases  in 
which  the  peripheral  parts  of  the  nerve  are  not  paralyzed, 
but  displaced,  as  happens  in  the  transposition  of  portions  of 
skin.  The  sensation,  being  the  same  as  before  the  transpo- 
sition, will  be  accompanied  by  the  same  localizing  operation, 
and  will  appear  situated  in  the  original  spot.  In  fact,  "  when, 
in  the  restoration  of  the  nose,  a  flap  of  skin  is  turned  down 
from  the  forehead  and  made  to  unite  with  the  stump  of  the 
nose,  the  new  nose  thus  formed  has,  as  long  as  the  isthmus 
of  skin  by  which  it  maintains  its  original  connections  remains 
undivided,  the  same  sensations  as  if  it  were  still  on  the  fore- 
head ;  in  other  words,  when  the  nose  is  touched  the  patient 
feels  the  impression  on  the  forehead."*  We  may  confidently 
decide,  then,  that  the  sensation,  though  really  situated  in 
the  sensory  centres,  has  the  property,  at  least  in  our  present 
state,  of  invariably  appearing  to  be  situated  elsewhere. 

Let  us  follow  out  the  examination ;  our  assurance  will  be 
further  strengthened,  and  we  shall  begin,  at  the  same  time, 
to  distinguish  the  law  which  regulates  the  localizing  opera- 
tion.— In  all  the  foregoing  cases  it  localized  our  sensation 
at  the  periphery  of  the  nerve,  from  which  the  nervous  dis- 
turbance resulting  in  the  sensation  usually  starts.  But  this  is 
not  always  so.  There  are  parts  of  our  bodies,  like  the  teeth 
and  hair,  which  are  not  provided  with  nerves,  and  which  are, 
in  themselves,  wholly  insensible ;  but  still  we  situate  many 
of  our  sensations  at  the  external  extremities  of  these  parts, 
where  no  nervous  disturbance  can  possibly  be  produced.f 
"  If  some  part  of  the  beard,"  says  Weber,  "  for  instance,  at 
the  side  of  the  cheek,  be  lightly  touched,  where  do  we  imagine 
that  we  feel  this  pressure  exercised  on  the  hairs  of  our  skin  ? 


*  Mueller,  op.  cit.  (tr.  Baly),  i.  697. 

f  Weber,  Article   Tastsinn  in  the  "  Handworterbuch  "  of  Rudolph  Wagner, 
iii,  part  ii.  p.  488  et  seq. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  201 

Not  in  the  sensible  parts,  to  which  it  is  propagated  through 
the  horny  cylinders,  and  at  which  it  acts  on  our  nerves,  but 

at   some   distance   from  the  skin If  we  put  a  little 

piece  of  wood  between  our  teeth,  and  press  it  with  them, 
we  imagine  the  resistance  it  offers  to  be  situated  at  the  sur- 
face of  the  teeth,  where,  however,  there  are  no  nerves, 
and  where,  consequently,  we  can  feel  nothing.  On  the 
other  hand,  we  have  no  feeling  whatever  of  the  pressure  ex- 
ercised on  the  internal  surface  of  the  root  of  the  tooth  in  the 
alveolus  in  which  it  is  hidden  ;  though  this  is  where  the  pro- 
pagated pressure  is  actually  exercised  upon  the  highly  ner- 
vous membrane  surrounding  the  root  of  the  tooth,  and  is  the 
only  spot  at  which  it  acts  on  our  nerves." — Further  than  this  : 
"  not  only  do  we  wrongly  situate  pressure  acting  on  the  sur- 
face of  the  insensible  substances  growing  from  our  skin,  but 
we  also  make  the  same  error  when  we  place  a  little  stick  be- 
tween our  fingers  and  feel  with  it  a  resisting  body,  as  for  in- 
stance, the 'table."  In  this  case,  two  sensations  are  simultane- 
ously produced,  one  which  appears  to  be  situated  at  the  ex- 
tremity of  our  fingers,  the  other  at  the  extremity  of  the  stick. 
If  the  stick  be  fixed  to  the  extremity  of  our  fingers  and  mov- 
able at  the  other  end,  the  first  sensation  is  effaced  and  the 
second  predominates.  If  the  stick  is  movable  at  the  extrem- 
ity of  our  fingers  and  fixed  at  the  other  extremity,  the  inverse 
is  the  case. — By  this  experiment  we  determine  the  law  of  the 
operation ;  evidently,  the  localizing  judgment  situates  each 
of  our  sensations  in  the  spot  in  which  we  are  accustomed  to 
meet  with  the  cause  or  condition  which  is  accustomed  to  ex- 
cite it.*  If,  from  birth,  the  stick  had  been  attached  to  one 
of  our  hands,  like  the  long  sensitive  exploring  whiskers  of  a 


*  Vulpian. — "  Lemons  sur  la  Physiologic  du  Systeme  Nerveux,"  287.  Experi- 
ment of  Paul  Bert. 

The  tail  of  a  rat  is  cut  raw  with  a  bistoury  and  implanted  in  the  animal's  back, 
where  it  becomes  grafted.  The  tail  is  then  divided  at  about  a  centimetre  from  its 
root.  The  rat  will  then  have  it  growing  backwards,  out  of  its  back.  For  the  first 
three  months,  there  are  feeble  signs  of  sensibility  when  the  tail  is  pinched.  "  After 
six  or  nine  months,  the  sensibility  is  much  increased,  but  the  animal  does  not  yet 
recognize  the  spot  in  which  he  is  pinched.  After  a  year,  he  is  perfectly  aware  of 
the  spot,  and  will  turn  round  to  bite  the  pincers."  We  see  here  the  proof  that  ex- 
perience must  intervene  to  enable  the  animal  to  localize  its  sensations. 


292  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

cat  are  attached  to  its  cheeks  and  lips,  like  the  stag's  horn  is 
attached  to  its  brow,  and  our  beard  and  teeth  are  attached  to 
our  membranes,  we  should  situate  things  we  came  into  con- 
tact with  at  the  end  of  the  stick,  as  the  cat  probably  situates 
what  it  touches  at  the  end  of  its  whiskers,  and  the  stag  at  the 
end  of  its  horns,  as  it  is  very  certain  we  situate  our  contacts 
at  the  extremities  of  our  beard  and  teeth. 

III.  The  consequence  is  that  when  a  sensation  has  for  its 
usual  condition  the  presence  of  an  object  more  or  less  distant 
from  our  bodies,  and  experience  has  once  made  us  acquainted 
with  this  distance,  we  shall  situate  our  sensation  at  this  dis- 
tance.— This,  in  fact,  is  the  case  with  sensations  of  hearing 
and  sight.  The  peripheral  extremity  of  the  acoustic  nerve 
is  in  the  deep-seated  chamber  of  the  ear.  That  of  the  optic 
nerve  is  in  the  most  inner  recess  of  the  eye.  But  still,  in  our 
present  state,  we  never  situate  our  sensations  of  sound  or 
color  in  these  places,  but  without  us,  and  often  at  a  consid- 
erable distance  from  us.  The  ringing  of  a  great  bell  seems 
to  vibrate  high  in  the  air  and  very  far  off;  a  railway  whistle 
seems  to  pierce  the  air  at  some  fifty  paces  to  the  left. — The 
position,  even  when  distant,  is  clearer  still  in  the  case  of  visual 
sensations.  This  extends  so  far  that  our. sensations  of  color 
seem  detached  from  us ;  we  no  longer  observe  that  they  ap- 
pertain to  us ;  they  seem  to  form  a  part  of  the  objects  ;  we 
believe  that  the  green  color  which  seems  extended  three  paces 
from  us  on  the  surface  of  this  arm-chair  is  one  of  its  properties  ; 
we  forget  that  it  only  exists  in  our  retina,  or  rather  in  the 
sensory  centres  which  the  disturbance  of  the  retina  disturbs. 
If  we  look  there  for  it,  we  shall  not  find  it  there  ;  physiologists 
may  prove  indeed  that  the  nervous  disturbance  which  results 
in  a  sensation  of  color  commences  in  the  retina,  just  as  the 
nervous  disturbance  which  results  in  a  sensation  of  contact 
commences  in  the  nervous  extremities  of  the  hand  or  foot  ; 
they  may  prove  that  the  vibrating  ether  strikes  the  extremity 
of  the  optic  nerve,  as  a  vibrating  tuning-fork  strikes  the  sur- 
face of  the  hand :  "  we  have  not  the  least  consciousness  of 
this  impression  on  the  retina,  even  when  we  direct  the  whole 
force  of  our  attention  to  the  spot.  * — -All  our  sensations  of 

*  Weber,  ibid.  482. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  293 

color  are  thus  projected  out  of  our  body,  and  clothe  more  or 
less  distant  objects  furniture,  walls,  houses,  trees,  the  sky, 
and  the  rest.  This  is  why,  when  we  afterwards  reflect  on 
them,  we  cease  to  attribute  them  to  ourselves;  they  are 
alienated  and  detached  from  us,  so  far  as  to  appear  different 
from  us.  Projected  from  the  nervous  surface  in  which  we 
localize  the  majority  of  the  others,  the  tie  which  connected 
them  to  the  others  and  to  ourselves  is  undone,  and  it  is  un- 
done in  accordance  with  a  well-known  mechanism,  by  the  ob- 
literation of  the  imaginative  operation  which  situates  the  sen- 
sation in  some  particular  spot. 

In  fact,  as  far  as  we  are  concerned,  this  operation  is  but 
a  means:  we  pay  no  attention  to  it ;  the  color  and  the  object 
denoted  by  the  color  are  what  alone  interest  us.  Conse- 
quently, we  forget  or  omit  to  observe  the  intermediate  steps 
by  which  we  localize  our  sensation ;  they  are  to  us  as  though 
they  did  not  exist ;  and  we  thereupon  consider  that  we  di- 
rectly perceive  the  color  and  colored  object  as  situated  at  a 
certain  distance  off. — In  consequence  of  this,  a  contrast  is 
established  between  this  sensation  and  others.  The  others 
seem  to  be  situated  in  a  body  belonging  to  us  and  specially 
connected  with  us,  which  we  move  at  will,  which  accom- 
panies us  in  all  our  changes  of  place,  which  answers  to  all 
our  touchings  by  a  sensation  of  contact,  in  which  we  situate 
ourselves  in  such  a  way  that  it  extends  over,  encloses,  and 
circumscribes  our  personality.  Our  sensations  of  color  seem, 
on  the  contrary,  situated  beyond  this,  on  the  surface  of  bodies 
foreign  to  ours,  beyond  the  limited  constant  circle  in  which 
we  are  enclosed.  There  is  nothing  strange,  then,  if  we  cease 
to  consider  them  as  belonging  to  us,  and  end  by  considering 
them  as  something  foreign  to  us.  If  they  are  fugitive  as  a 
flash  of  lightning,  the  ring  of  fire  described  by  whirling  round 
a  burning  coal,  or  an  impalpable  meteor,  they  seem  to  us  a 
simple  event  with  position  and  shape.  If,  as  usually  happens, 
they  are  stable  like  the  color  of  a  stone,  of  a  flower,  of  a  tan- 
gible object,  they  seem  to  us  a  more  or  less  permanent  and  fixed 
quality  of  that  object. 

The  reason  of  this  is  evident.  As  long  as  we  rest  our  eyes 
on  the  gilded  frame  of  this  mirror,  the  long  yellow  stripe  per- 


294  THE  KNOWLEDGE   OF  BODIES.  fBooK  II. 

sists  unchanged ;  the  uniform,  incessant,  prodigiously  rapid 
renewal  of  the  vibrations  of  ether  maintains  it  without  alter- 
ation or  discontinuity ;  it  does  not  disappear  unless,  by  a 
voluntary  and  foreseen  movement  of  which  I  have  sensation 
and  recollection,  I  turn  away  my  eyes  and  head. — More- 
over, whenever  I  look  again  for  this  yellow  stripe,  I  invariably 
find  it  in  the  same  relative  position,  to  the  right  of  the  dark 
glittering  surface  presented  by  the  mirror,  to  the  left  of 
the  striped  gray  presented  by  the  paper  of  the  wall. — Further 
still,  the  little  bright  or  dark  bands  formed  by  the  reliefs  and 
hollows  of  the  chasing  always  preserve  the  same  relative  pos- 
itions in  the  whole  yellow  stripe.  Consequently,  this  yellow 
is  not  a  transitory  momentary  thing  like  a  flash  of  lightning  ; 
it  does  not  cease  of  its  own  accord.  Experience  shows  me 
that  I  am  sure  of  finding  it  again  whenever  I  please  ;  from 
finding  it  present,  whenever  I  have  turned  my  eyes  towards 
it  in  the  light,  I  conclude  by  induction  that  it  is  constantly 
present,  all  circumstances  remaining  the  same,  at  whatever 
moment  of  time  I  have  turned  or  may  turn  my  eyes  towards 
it,  in  any  moment  whatever  of  the  past  or  the  future ;  there- 
fore it  occupies  them  all.  Its  existence  past  and  future  is  thus 
prolonged  indefinitely,  and  it  is  the  same  in  all  these  dis- 
tinct instants.  It  seems,  then,  a  permanent  quality  in  that 
group  of  permanent  possibilities  we  term  body. 

The  truth,  however,  is  that  all  the  colors  with  which  the 
surrounding  world  seems  decked  are  within  us,  and  are  sen- 
sations of  our  optic  centres ;  the  consideration  of  the  sensa- 
tions of  sight  we  term  subjective  is  sufficient  to  convince  us  of 
this.  These  sensations  undeceive  and  instruct  us  with  respect 
to  sight,  just  as  the  illusions  of  persons  who  have  suffered 
amputations  do  with  respect  to  touch.  Color  is  not  in  the 
object,  nor  in  the  luminous  rays  which  spring  from  it ;  for,  in 
many  instances,  we  see  it  when  the  object  is  absent,  and  when 
the  luminous  rays  are  wanting.  The  presence  of  the  object 
and  of  the  luminous  rays  contribute  indirectly  only  to 
cause  it  to  rise ;  its  direct  necessary  and  sufficient  condition 
is  the  excitation  of  the  retina,  or  which  is  more  important  of 
the  optic  centres  of  the  encephalon.  It  matters  little  whether 
this  excitation  be  produced  by  an  impingement  of  luminous 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  295 

,rays,  or  otherwise.  It  matters  little  whether  it  be  spontaneous 
or  not.  Whatever  be  its  cause,  as  soon  as  it  arises,  the  color 
arises,  and,  at  the  same  moment,  that  which  we  term  the 
visible  figure.  Consequently,  the  color  and  visible  figure  are 
but  internal  events,  which  appear  external.  The  whole  of 
physiological  optics  rests  on  this  principle,  and,  to  convince  our- 
selves of  its  soundness,  we  have  but  to  look  at  a  few,  among 
the  hundreds  of  cases  in  which  apparent  color  and  figure  arise 
of  themselves,  without  any  external  object  or  pencil  of  lumin- 
ous rays  directly  or  indirectly  setting  the  nerve  in  action. 
When  we  have  been  looking  steadfastly  at  a  luminous  or 
strongly  illuminated  object  the  excitation  of  the  retina  per- 
sists after  we  have  ceased  to  look.*  Hence  arise  the  singu- 
lar phenomena  termed  consecutive  images.  These,  in  fact,  are 
complete  visual  sensations  which  survive  and  are  prolonged 
in  the  absence  of  their  object.  According  to  circumstances, 
in  some  cases  the  brighter  portions  of  the  consecutive  image 
correspond  to  the  brighter  portions  of  the  object,  and  the 
darker  portions  of  the  image  to  the  darker  portions  of  the 
object,  and  in  some  cases  the  inverse.  In  the  second  case, 
the  colors  of  the  consecutive  image  are  the  complementaries 
of  the  colors  of  the  object  ;  that  is  to  say,  where  the  object  is 
red,  the  image  is  of  a  greenish  blue;  where  the  object  is  yel- 
low, the  image  is  blue  ;  where  the  object  is  green,  the  image 
is  rose-colored,  and  vice  versa. — A  number  of  analogous  phe- 
nomena have  been  observed,  arid  are  explained  by  the  persist- 
ing excitation  and  diminished  excitability  of  the  retina  after 
undergoing  the  action  of  light. — But  there  are  other  phenom- 
ena of  the  same  kind,  which  are  produced  without  there  be- 
ing any  need  for  the  intervention  of  light.  It  is  enough  in 
these  cases  if  the  retina  be  set  in  action  by  some  other  cause. f 
If  the  eye  be  compressed  with  the  finger  we  see  luminous  fig- 
ures "  sometimes  annular,  sometimes  radiated,  sometimes  di- 
vided regularly  into  squares.  If  in  a  room  otherwise  dark,  a 
lighted  candle  be  moved  to  and  fro,  or  in  a  circle,  about  six 
inches  from  the  eyes,  we  soon  see  a  dark  arborescent  figure 

*  Helmholtz,"  Physiologische  Optik,"  356  ;    Mueller,  "  Physiology"  (tr.  Baly). 
ii.  1394- 

f  Helmholtz,  ib.  418  ;  Mueller,  op.  cit.  (tr.  Baly),  ii.  1163. 


296  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

whose  branches  extend  over  the  whole  field  of  vision,  and 
which  is  nothing  more  than  the  expansion  of  the  central  ves- 
sels of  the  retina,  or  that  of  the  parts  of  the  retina  covered  by 
those  vessels."  Sometimes,  after  compressing  the  eye,  this 
arborescent  figure  appears  luminous.  "  Luminous  moving 
points  appear  in  the  field  of  vision  when  we  look  fixedly  at  a 
surface  uniformly  illuminated,  as,  for  instance,  the  sky,  or  a 
field  of  snow,  and  especially  during  a  brisk  walk  or  some  other 
movement  of  the  body."  In  cases  of  plethora  or  congestion, 
"  when  we  have  been  lying  down  and  suddenly  rise  up,  we 
see  a  number  of  little  black  bodies  with  tails  to  them  jump- 
ing and  moving  in  all  kinds  of  directions." — Different  narcot- 
ics, digitalis  especially,  excite  flashings  in  the  eyes. — And  so, 
when  disease  inflames  or  irritates  the  retina,  flashes  and 
sparks  are  perceived,  and,  in  surgical  operations,  which  neces- 
sitate the  section  of  the  optic  nerve,  the  patient  sees  great 
masses  of  light  at  the  moment  the  instrument  cuts  the  nerve. 
—But  the  retina  and  the  whole  optic  nerve  are  themselves 
but  intermediate  conductors  ;  they  serve  to  excite  the  optic 
centres  of  the  encephalon,  that  is  all.  Suppose  the  centres 
are  excited  and  the  conductors  inactive ;  the  colored  figure 
will  arise  and  appear  internal.  This  is  the  case  with  hallucin- 
ations of  sight  strictly  so  called,  in  which  a  reflected  excita- 
tion propagates  the  images  of  the  hemispheres  to  the  visual 
centres  of  the  encephalon.  This  is  the  case  with  the  appear- 
ance following  the  prolonged  use  of  the  microscope,  when  the 
visual  centres  of  the  encephalon  re-enter  several  times  spon- 
taneously into  the  state  in  which  the  action  of  the  retina  has 
set  them  too  often  and  retained  them  too  long.  These  cases 
all  resemble  that  in  which  a  spontaneous  disturbance  of  the 
acoustic  nerve  causes  us  to  hear  and  localize  at  a  particular 
distance,  and  in  a  particular  direction,  a  sound  which  there 
is  no  vibration  of  the  external  air  to  produce. 

Now  it  is  plain  that  the  color,  like  the  sound,  is  then  with- 
in us,  and  cannot  be  elsewhere  ;  and  still  we  project  it  with- 
out us,  and  situate  it  at  a  spot  where  it  cannot  be.  We  may 
know,  indeed,  by  reasoning  that  this  situation  is  illusory  ;  the 
appearance  is  too  strong  for  us ;  we  perceive  the  luminous 
bluish  circle  excited  by  a  pressure  at  the  inner  corner  of  the 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES. 


297 


eye,  as  if  it  were  situated  a  little  above  the  outer  corner,  not 
in  the  retina,  but  without  the  pupils.  Thus  when  we  are 
given  a  visual  sensation  to  which  no  external  object  corres- 
ponds, it  excites  the  play  of  an  internal  mechanism  which 
transports  it  without  us,  and  which,  according  to  its  kind,  and 
as  it  is  provided  with  certain  particular  accompaniments,  sit- 
uates it  in  one  spot  or  another,  always  at  the  place  in  which, 
under  ordinary  circumstances,  its  ordinary  cause  or  condition 
usually  is  :  the  law  is  a  general  one,  and  explains  all  the  illu- 
sions of  optics. — Consequently,  even  under  ordinary  circum- 
stances, when  the  ordinary  cause  or  condition,  that  is  to  say 
the  object,  is  present,  and  occupies  the  spot  denoted,  when  a 
red  arm-chair  or  a  green  tree  is  really  six  paces  from  me,  the 
internal  mechanism  acts  just  as  in  the  exceptional  case  in 
which  I  have  a  consecutive  impression  on  the  retina,  or  in  the 
exceptional  case  in  which  I  have  an  hallucination  proper  in 
the  cerebral  centres.  Consequently,  too,  the  red  color  with 
which  the  arm-chair  is  clothed,  the  green  color  which  seams 
to  me  incorporated  with  the  tree,  is  nothing  more  than  my 
sensation  of  red  or  of  green,  detached  from  myself  and  car- 
ried, in  appearance,  to  a  distance  of  six  paces  from  my  eyes. 

Thus,  all  our  sensations  are  wrongly  situated,  and  the  red 
color  is  no  more  extended  on  the  arm-chair  than  the  sensa- 
tion of  tingling  is  situated  at  my  fingers'  ends.  They  are  all 
situated  in  the  sensory  centres  of  the  encephalon  ;  all  appear 
situated  elsewhere,  and  a  common  law  allots  to  each  of  them 
its  apparent  situation.  The  law  is — that  a  sensation  ap- 
pears to  us  to  be  situated  at  the  spot  in  which  we  are  accus- 
tomed to  meet  with  its  usual  cause  or  condition,  and  this 
spot  is  the  one  at  which  the  explorations  of  touch  are  capa- 
ble, by  acting  there,  of  checking  or  modifying  the  commenced 
sensation.  The  singularities,  errors,  and  diversities  of  the 
localizing  judgment  are  all  explained  by  this  law. 

In  the  first  place,  we  see  that  this  judgment  must  invaria- 
bly be  false ;  for  the  touch  can  never  arrive  at  the  sensory 
centres,  to  check  or  modify  the  commenced  sensation ;  the 
sensory  centres  are  in  the  box  of  the  cranium  in  a  place  our 
hands  cannot  reach.— Secondly,  we  see  that  in  most  cases  the 
localizing  judgment  must  situate  the  sensation  somewhere 


2^8  THE  KNOWLEDGE   OF  BCDIES.  [Boon  II. 

near  the  peripheral  extremity  of  the  nerves  ;  for,  though  the 
excitation  of  the  whole  course  of  the  nerve  is  the  normal  an- 
tecedent of  sensation,  our  touch  can  only  attain  the  parts  ad- 
joining the  peripheral  extremity.  It  is,  then,  at  this  point 
and  no  other  of  the  nervous  cord,  that  the  localizing  judg- 
ment must  situate  the  sensation.  And  this  is  true  for  all  sen- 
sations, even  for  sensations  of  sight,  at  least  in  the  first  stage 
of  their  localization  ;  in  fact,  we  shall  presently  show  that  per- 
sons born  blind,  at  the  moment  a  surgical  operation  restores 
their  sight,  situate  colors  near  the  periphery  of  the  optic 
nerve  ;  it  is  later  on,  after  a  further  apprenticeship,  that  they 
refer  them  beyond  this,  to  the  place  where  the  objects  are 
situated. — Thirdly,  we  see  that  the  localizing  judgment  can- 
not situate  sensations  at  the  exact  spot  of  the  periphery  of 
the  nerve  in  action,  but  in  its  neighborhood,  and  in  general  a 
little  beyond  it  ;  for  the  touch  cannot  reach  the  exact  spot.  The 
finger  cannot  reach  the  retina  at  the  back  of  the  eye,  nor  the 
pituitary  membrane  at  the  inner  part  of  the  nose,  nor  the 
acoustic  nerve  in  the  labyrinth  of  the  ear,  nor,  in  general,  any 
nervous  periphery.  What  it  reaches,  are  the  envelopes  and 
appendages  of  the  nerve,  the  eyeball,  the  vestibule  of  the  ear, 
the  anterior  chamber  of  the  nose,  the  surface  of  the  skin. 
There  it  is  that  it  checks  and  modifies  the  commenced  sensa- 
tion, or  associates  with  it  a  sensation  of  contact.  There, 
then,  it  is  that  we  must  situate  the  sensation,  and  it  is  the 
same  with  sensations  of  sight  as  with  all  the  rest ;  persons 
born  blind,  who  have  lately  been  operated  on,  situate  their 
new  sensations  at  the  surface  of  the  eyeball,  and  not  at  the  back 
of  the  orbit. — Fourthly,  we  see  that  in  many  cases  the  localiz- 
ing judgment  must  be  vague ;  for  there  are  places  which 
touch  cannot  reach,  for  instance,  the  internal  parts  of  the 
limbs  and  trunk  ;  consequently,  we  situate  approximately  and 
vaguely  all  the  sensations  whose  starting  point  is  in  the  belly, 
the  chest,  the  stomach,  just  as  we  do  the  partial  sensations  of 
which  a  total  muscular  sensation  is  composed. — Numbers  of 
strange  appearances  are  explained  in  the  same  way.  If  the 
exploration  of  touch  is  brought  to  a  stop  by  a  fixed  eminence 
like  the  teeth,  the  sensation  will  appear  to  be  situated  at  the 
surface  of  the  eminence,  though  the  nervous  disturbance  is 


CHAP.  II.]  THE  EDUCATION  OF  THE   SENSES.  299 

much  lower  down. — If  the  exploration  of  touch  cannot  verify 
the  positions  of  the  two  nervous  disturbances,  one  of  which 
is  situated  above,  the  other  below,  as  happens  with  impres- 
sions of  the  retina,  and  if,  at  the  same  time,  it  finds  the  two 
external  conditions  of  these  two  impressions  situated  in  an 
inverse  order  with  relation  to  each  other,  as  happens  with  vis- 
ible objects,  we  shall  situate  in  the  inverse  order  the  two  sen- 
sations derived  from  them.  In  fact,  images  of  objects  are  re- 
versed upon  the  retina  ;  the  feet  of  a  figure  are  above  and  the 
head  below,  and  nevertheless,  we  situate  the  head  above  and 
the  feet  below.  The  apparent  position  of  our  two  sensations 
is  thus  found  to  be  the  inverse  of  the  real  position  of  the  two 
disturbances. 

It  remains  to  be  shown  how,  in  accordance  with  the  same 
law,  the  localizing  judgment  situates  certain  kinds  of  sensations 
beyond  our  nervous  superfices.  The  fact  is,  there  are  two 
stages,  and  the  judgment,  according  to  the  nature  of  the  sen- 
sation, stops  at  the  first  or  goes  on  to  the  second. — Two  kinds 
of  sensations,  the  visual  and  auditory,  can  alone  pass  through 
b6th  stages ;  they  alone  are  clearly  projected  from  their  first 
position  to  some  particular  spot  or  other  of  the  outside 
world.  The  fact  is,  they  alone  furnish  materials  for  an  ulte- 
rior localization. — Take,  for  instance,  two  visual  sensations. 
Not  only  have  they  a  common  organic  condition,  the  modifi- 
cation of  the  open  eye,  but  besides  they  have  each  of  them  a 
special  external  condition,  the  presence  in  a  particular  spot  of 
the  outer  world  of  an  illuminated  body,  a  condition  to  which 
there  corresponds  in  them  some  precise  and  notable  character, 
according  as  the  body  is  in  one  place  or  another.  When  by 
feeling  with  the  hand  or  by  closing  the  eyelids,  we  have 
proved  their  common  organic  condition,  we  prove,  by  other 
feelings,  and  by  changing  our  position,  their  different  external 
conditions.  We  have  interrupted  all  our  visual  sensations,  by 
the  same  act — by  closing  our  eyelids ;  we  interrupt  our  differ- 
ent visual  sensations  in  different  manners,  by  extending  our 
arm  more  or  less,  by  increasing  our  change  of  position,  by 
covering  with  our  hand  the  illuminated  surface  of  the  body 
which  emits  the  rays.  Now,  these  are  the  only  differences 
which  can  interest  us  ;  for  these  are  the  only  indications  which 


300  THE  ^vo  WLEDGE   OF  BODIES.  [BOOK  II. 

direct  our  action  ;  they  alone  suggest  to  us  the  number  of 
steps  and  the  extent  of  the  movement,  by  which,  through 
reaching  the  object,  we  reproduce  in  ourselves  some  anterior 
state  which  was  agreeable  or  useful  to  us,  or,  by  which,  in  re- 
moving ourselves  from  the  object,  we  avoid  some  anterior 
state  which  was  displeasing  or  hurtful.— Our  attention,  then, 
is  directed  solely  to  these  ;  the  general  association  which  had 
first  joined  our  different  visual  sensations  to  the  idea  of  the 
movement  by  which  our  hand  reaches  our  eye,  is  effaced  as 
useless  ;  the  education  of  the  eye  is  accomplished  ;  useful  as- 
sociations become  established  and  alone  subsist.  Each  dis- 
tinct visual  sensation  is  combined  with  the  idea  of  a  distinct 
movement  of  more  or  less  length,  effected  in  one  or  another 
direction  ;  it  takes  this  idea  as  its  associate  ;  henceforward,  it 
is  inseparable  from  it.  By  this  combination,  it  becomes  situ- 
ated at  a  greater  or  less  distance,  in  one  place  or  another,  but 
always  in  the  outer  world. 

The  same  reasoning  applies  to  the  place  of  auditory  sen- 
sations.— Now,  if  these  two  sorts  of  sensations  have  this  sin- 
gular peculiarity,  it  is  because,  by  a  special  peculiarity,  there 
corresponds  to  each  variation  in  the  situation  of  their  distant 
cause,  a  precise  variation  in  the  sensations  themselves.  We 
shall  see  later  on  how  the  precise  variations  of  the  sensation 
of  sight  are  effected  by  the  adjustment  of  the  crystalline  lens, 
the  greater  or  less  convergence  of  the  two  eyes,  the  contrac- 
tion of  the  motor  muscles  of  the  eye.  With  respect  to  hear- 
ing, whose  localizations  are  less  exact,  variations  less  precise, 
but  still  precise,  are  furnished  by  the  greater  or  less  intensity 
of  the  whole  sensation  entering  both  ears,  and  by  the  greater 
intensity  of  one  of  the  two  component  sensations. — It  is  not 
the  same  with  the  other  senses.  Their  sensations  indicate 
nothing,  or  next  to  nothing,  as  to  position.  For,  first,  a  sen- 
sation of  contact,  of  pressure,  of  taste,  is  only  produced  when 
the  external  cause  touches  the  skin,  the  mouth,  or  the  palate  ; 
at  a  distance,  this  cause  does  not  operate :  this  is  how  the 
sensation  which  it  excites  does  not  vary  according  to  dis- 
tance ;  the  localization  remains  checked  at  its  first  stage,  and 
we  situate  the  sensation  at  or  near  the  place,  in  which  the  ex- 
plorations of  touch  meet  with  its  organic  condition. — As  to 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  3OI 

sensations  of  smell  and  heat,  in  certain  cases,  and  up  to  a  cer- 
tain point,  we  are  capable  of  appreciating  vaguely,  by  the 
force  or  feebleness  of  the  sensation,  whether  its  origin  is  near 
or  distant ;  sometimes  we  can  even  distinguish  whether  it  is 
on  our  left  hand  or  right ;  but  it  is  nearly  always  necessary  to 
make  a  new  examination.  When  our  eyes  are  shut,  we  dis- 
cover by  smelling  about,  by  turning  the  head  in  different  di- 
rections, that  the  smell  comes  from  a  bouquet  placed  on  a  par- 
ticular side  of  us,  that  the  cold  comes  from  a  particular  chink. 
But  we  do  not  know  this  with  precision  and  at  once  ;  the 
idea  of  a  certain  movement  of  measurement  does  not  present 
itself  immediately,  by  virtue  of  an  ancient  and  fixed  connec- 
tion, and  attach  itself  to  the  sensation  so  as  to  localize  it  in 
one  spot  rather  than  another  of  the  outer  world.  Conse- 
quently, we  remain  in  suspense  ;  we  are  tempted  to  consider 
our  sensation,  sometimes  as  a  sensation,  sometimes  as  an  un- 
known thing  which  starts  from  without  and  enters  us.  The 
words  smell,  cold,  heat,  remain  ambiguous,  and  denote,  in  or- 
dinary language,  sometimes  the  one,  sometimes  the  other; 
this  is  because  the  second  stage  of  localization  has  commenced 
and  broken  down.  It  would  not  break  down  if  the  nostrils 
were  placed  like  the  ears,  on  the  two  opposite  sides  of  the 
head,  and  could  thus  discern  in  a  whole  sensation  of  smell,  two 
sensations,  one  stronger  than  the  other,  or  if  there  were  two 
symmetrical,  distinct  and  opposed  portions  of  the  body  charged 
to  receive  sensations  of  heat. — We  see  that  the  sajfte^aw-ws*^,, 
plains  both  the  definite  and  the  indefinite '  sitw^utffl^V'e-  attri- 
bute to  our  sensations,  sometimes  in  the  neighborhood  of  the 
peripheral  extremities  of  the  nerves,  sometimes  elsewhere  and 
at  a  greater  distance.  ^ 

To  sum  up,  in  our  present  state,  the  situafWi  we  attribute 
to  our  sensations  is  always  false  ;  that  which  is  sre^U^d-at  .the,  v 
spot  in  which  we  place  them  is  their  usual  cause  or  condition, 
sometimes,  the  organ  in  which  the  primary  nervous  distur- 
bance of  which  they  are  the  result  is  effected,  sometimes,  the 
external  object  which  excites  the  nervous  disturbance.  This 
cause  or  condition  may  be  absent,  as  its  presence  is  usual 
only  ;  in  any  case,  whether  present  or  absent,  the  localizing 
judgment  is  an  illusion,  since  we  invariably  situate  the  sen- 


302  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

sation  where  it  is  not.  Usually,  this  judgment  is  practically 
effective,  through  the  provisions  it  suggests  and  which  direct 
our  conduct ;  in  itself  it  is  nothing  more  than  an  illusion, 
which  is  generally  useful,  a  fundamental  error  which  nature 
and  experience  have  constructed  within  us  and  established  in 
us  perpetually,  to  act  as  a  preservative  of  our  life,  and  an  or- 
gan for  our  action. 

IV.  The  localizing  judgment  remains  itself  to  be  studied. 
—To  see  of  what  elements  it  is  composed,  let  us  revert  to  our 
first  example.  I  have  just  put  my  foot  to  the  ground,  I  feel 
a  sensation  of  pressure,  and  at  the  same  time  determine  the 
place  of  the  sensation  ;  it  is  in  my  left  foot,  strong  in  the  mid- 
dle of  the  foot,  slight  towards  the  heel,  almost  imperceptible 
at  the  toes.  In  what  do  these  last  observations  consist  ? — • 
Each  one  of  us  may  observe  in  his  own  case  that,  in  order  to 
make  them,  we  imagine  with  more  or  less  clearness  the  foot 
in  question,  and  imagine  it  visually,  that  is  to  say  by  images 
of  the  optical  sensation  it  would  excite  in  us,  if  we  were  then 
looking  at  it  with  our  eyes  open.  We  picture  to  ourselves 
the  foot  at  a  certain  distance  from  our  eyes,  the  curvature  of 
the  sole,  the  form  of  the  heel,  the  row  of  toes.  We  even,  if 
we  persist,  see  mentally  the  color  of  the  flesh,  browner  to- 
wards the  heel,  whiter  at  the  sole,  and  redder  beneath  the 
toes.  In  fact,  we  have  within  us  a  visual  chart  of  our  body. 
We  represent  it  to  ourselves  just  as  we  should  any  other  ob- 
ject of  which  we  have  ocular  experience.  To  each  distinct 
sensation  there  is  in  the  chart  a  distinct  corresponding  point, 
which  has  been  associated  with  the  sensation  by  experience. 
When  the  sensation  arises,  this  point  revives,  and  their  junc- 
tion situates  the  sensation  in  some  particular  one  of  the  dif- 
ferent points  of  the  field  which  actual,  or  simply  mental  sight 
is  accustomed  to  traverse. 

But  it  is  evident  that  a  chart  like  this  is  an  ulterior  and 
special  acquisition.  It  is  wanting  to  persons  born  blind,  and 
still  they  are  perfectly  able  to  denote  the  position  of  their 
sensations.  They  have  then  another  chart  which  fulfils  the 
same  office,  and,  as  we  have  all  their  sensations,  in  addition 
to  the  sight  which  they  do  not  possess,  it  follows  that  we  pos- 
sess a  second  and  wholly  different  chart,  which  is  common  to 


CHAP.  II. j  THE  EDUCATION  OF   THE   SENSES.  303 

us  with  them,  in  addition  to  the  visual  chart,  which  is  special 
to  ourselves. — This  second  chart  has  as  its  elements  muscular 
and  tactile  sensations.  It  is  composed  of  the  images  of  these 
sensations,  and,  in  many  instances,  we  prove  their  existence 
in  ourselves,  as,  for  example,  with  respect  to  portions  of  our 
body  which  we  cannot  observe  with  our  eyes,  and  as  to  which 
the  visual  chart  is  consequently  not  clear. — Such,  for  instance, 
is  the  inside  of  the  mouth,  which  we  can  only  see  by  the  aid 
of  a  glass,  the  back  of  the  head,  of  the  neck,  of  the  trunk,  of 
the  thighs,  which  we  can  only  see  by  the  aid  of  two  glasses. 
In  fact,  for  all  these  spots,  we  form,  from  others,  a  sort  of  ap- 
proximate chart  of  ourselves.  But  this  plate  of  our  visual 
atlas  is  vague,  and  we  seldom  have  recourse  to  it.  I  experi- 
ence an  itching  at  a  point  of  my  back,  and  I  know  the  spot ; 
but  I  do  not  know  it,  or  only  know  it  imperfectly,  by  the  vis- 
ual representation  ;  I  do  not  picture  clearly  to  myself  the  ver- 
tebra or  the  rib,  the  swelling  of  the  muscle  or  spinal  hollow, 
near  which  the  feeling  is  ;  it  is  not  associated,  as  in  the  hand, 
the  foot,  the  arm,  or  the  face,  with  some  precise  point  of  an 
outline  pictured  by  the  mental  eye.  It  is  by  means  of  another 
atlas,  the  tactile  and  muscular  atlas,  that  I  am  enabled  to  situ- 
ate it  precisely. 

In  fact  I  give  it  a  situation  by  means  of  the  special,  longer 
or  shorter  muscular  sensation  of  the  hand  and  arm,  which 
move  towards  it  and  reach  it.  Its  position  is  denoted  by  the 
nature  and  duration  of  this  sensation.  If  at  a  greater  dis- 
tance, a  greater  movement  would  be  required  to  reach  it,  con- 
sequently a  longer  muscular  sensation  ;  if  at  a  less  distance,  a 
less  movement,  consequently  a  shorter  muscular  sensation  ; 
if  at  the  same  distance,  but  in  a  different  direction,  a  move- 
ment equal  in  extent,  but  different,  consequently  a  muscular 
sensation  of  equal  duration,  but  different.  By  means  of  these 
repeated  and  diversified  experiments,  when  a  sensation, 
whether  of  tingling  or  any  other,  is  aroused  in  any  part  of  my 
body,  even  in  a  point  with  respect  to  which  the  visual  atlas, 
fails,  it  calls  up  its  inseparable  associate,  the  image  of  a  spe- 
cial muscular  sensation,  a  sensation  of  a  precise  duration, 
longer  than  some  other  similar  one,  shorter  than  some  other 
similar  one,  different  from  some  other  one  of  equal  length. 


304  TIIE  KNO  WLEDGE   OF  BODIES.  [BOOK  II 

By  this  attachment  and  consolidation,  my  sensation  of  ting- 
ling finds  itself  denoted  by  a  distinctive  sign.  This  sign,  hav- 
ing a  certain  duration,  is  a  continuous  magnitude  ;  therefore 
it  is,  like  a  line,  capable  of  comparison  with  any  other  magni- 
tude of  the  same  kind,  it  differs  only  from  such  other  magni- 
tude in  being  more  or  less,  suggests  the  idea  of  its  double  or 
of  its  fraction,  and  is  capable  of  measurement ;  here  we  have 
the  conditions  of  a  representative  chart. — This  is  but  an  in- 
stance of  a  general  operation,  which  has  already  been  de- 
scribed. We  localize  our  sensations  as  we  do  objects,  by  the 
associated  image  of  certain  muscular  sensations  of  greater  or 
less  length.  The  sensation,  by  means  of  the  associated  im- 
age, is  arrested  in  an  order,  arid,  so  to  speak,  in  a  rank  ;  there 
it  is  situated,  that  is  to  say  denoted  by  a  precise  quantity, 
less  than  this,  greater  than  that,  by  a  muscular  reminiscence 
which  intercalates  it  between  two  series  of  muscular  sensa- 
tions, one  of  longer  sensations,  the  other  of  shorter  ones. — If 
we  add  the  reminiscence  of  the  tactile  sensations  experienced 
upon  contact  with  the  point  which  the  exploring  organ  has 
just  touched,  the  associated  image  becomes  precise  while  com- 
pleting itself;  we  situate  our  sensation,  not  only  at  a  particu- 
lar distance  from  some  other,  but  at  such  a  rib,  at  such  a  hol- 
low of  the  arm,  at  such  a  joint  of  the  finger. — Such  is  the 
tactile  and  muscular  atlas,  the  first  of  all  ;  the  instinctive  and 
unregulated  movements  of  the  new-born  child,  its  feelings 
about,  the  incessant  experience  it  acquires  of  its  touch  and 
muscles,  commence  at  once  to  construct  this  atlas  ;  the  visual 
atlas  is  derived  from  it,  and  is  not  formed  till  afterwards. 

Thus  the  localizing  judgment  consists  in  the  adjunction  to 
the  sensation  of  certain  images,  sometimes  visual,  sometimes 
tactile  and  muscular.  This  coupling  may  be  innate ;  the 
chicken  will  pick  up  food  immediately  it  comes  out  of  the 
shell ;  the  new-born  foal  springs  on  his  legs  almost  immedi- 
ately and  goes  to  suck  its  dam.  But  in  man  it  is  acquired,  and 
the  internal  mechanism,  which  in  other  animals  is  fabricated 
at  the  moment  of  birth,  is  in  his  case  fabricated  gradually. 
At  all  events,  it  is  for  the  most  part  a  work  of  experience. 
"  There  is  ground,"  says  Weber,*  "  for  admitting  that  primi- 

*  Article  "  Tastsinn,"  ibid.  486. 


CHAP.  II.]          THE  EDUCATION  OF   THE   SENSES.  305 

tively,  by  pure  sensation,  we  know  nothing  of  the  place  in  which 
the  nerves  which  communicate  the  sensation  to  us  are  disturb- 
ed. Primitively,  all  sensations  are  simple  states  of  excitation 
perceptible  to  consciousness  ;  these  may  differ  in  quality  and 
degree,  but  do  not  directly  furnish  to  consciousness  any  notion 
of  place.  They  only  furnish  this  indirectly,  by  exciting  the 
activity  of  our  mind,  through  the  means  of  which  we  repre- 
sent our  sensations  as  comprised  in  a  whole,  and  possessed  of 
mutual  relations."  There  is  then  an  ulterior  and  superadded 
process,  the  adjunction  of  a  series  of  muscular  images,  whose 
duration  measures  the  distance,  the  adjunction  of  a  group  of 
tactile  and  muscular  images  which  denote  the  consistence, 
shape,  and  magnitude  of  the  organ  to  which  the  sensation  is 
referred,  the  adjunction  of  a  group  of  visual  images  which  de- 
note this  organ  from  the  other  organs  and  other  objects  de- 
noted in  the  same  manner.  All  this  is  the  work  of  experience, 
and  experience,  pushed  further,  is  capable  of  associating  with 
the  sensation  representations  of  greater  exactness.  An  anat- 
omist who  bends  his  hand  imagines  the  contraction  of  each 
of  the  muscles  which  concur  in  effecting  it,  the  longer  and 
shorter  palmar  muscles,  the  anterior  cubital,  and  the  rest.  If 
he  is  pricked,  he  pictures  to  himself  the  form,  color,  and  dis- 
tribution of  the  little  whitish  flabby  threads  termed  nerves, 
which  the  puncture  has  touched.  He  represents  his  sensation 
of  contraction  as  being  situated  in  the  nerves  of  the  contrac- 
ted muscles,  and  his  sensation  of  pain  as  being  situated  in 
the  punctured  extremity  of  the  little  whitish  threads.  This 
association,  less  fixed  than  ours,  is  identical  with  ours,  and  is 
like  a  second  stage  of  less  solidity  based  on  a  first  indestruct- 
ible stage.  But  they  are  both  of  them  added  constructions, 
and  did  not  exist  on  the  primitive  soil. 

V.  If  we  now  compare  the  two  atlases,  we  shall  find  them 
very  different.  That  the  first,  the  tactile  and  muscular  atlas, 
is  effective  for  the  purpose  of  localizing  our  sensations  in 
some  particular  part  of  our  bodies  is  explainable  without 
difficulty ;  for  we  have  seen  that  we  conceive  extent,  dis- 
tance, and  position  by  a  series  of  muscular  sensations  inter- 
posed between  a  point  and  another  point — between  a  sen- 
sation and  a  sensation.  I  have  many  times  experienced  a 

20 


306  THE  KNOWLEDGE   OF  BODIES.  [Book  114 

feeling  of  touch  in  my  neck  or  cheek ;  I  have  determined 
its  position  by  the  series  of  muscular  sensations  which  my 
hand  must  go  through  to  reach  it,  and  have  characterized  its 
seat  by  the  group  of  tactile  sensations  of  my  hand  afforded 
by  my  neck,  when  it  is  pressed,  felt,  and  traversed.  A  stable 
association  is  thus  formed  between  the  sensations,  whose 
starting-point  is  in  the  nerves  of  the  neck,  and  this  series 
of  muscular  images  joined  to  this  group  of  tactile  images. 
Consequently,  whenever  a  similar  sensation  is  produced,  I 
shall  imagine  its  position  and  seat. — This  is  not  the  case 
with  the  visual  atlas,  and  we  must  examine  how  it  is  that 
sensations  of  the  eye,  which,  taken  alone,  seem  fit  only  to 
instruct  us  as  to  colors,  are  capable  of  further  instructing 
us,  as  to  distance,  extension  and  position.  This  arises 
from  their  being  themselves  transformed,  and  turned  into 
equivalents  of  tactile  and  muscular  sensations,  by  the  asso- 
ciation they  have  acquired  with  tactile  and  muscular  sen- 
sations. Primitively,  and  in  itself,  the  retina,  when  im- 
pressed, arouses  sensations  only  of  light,  of  obscurity,  of 
successive  and  simultaneous  colors.  It  is  by  an  ulterior 
process — the  adjunction  of  auxiliary  images — that  this  pure 
visual  sensation  receives  an  apparent  situation,  and  that  we 
see  objects  at  a  certain  distance,  in  a  particular  direction, 
with  particular  form  and  dimensions. 

The  accounts  of  persons  born  blind,  who  have  been 
restored  to  sight  by  operations,  is  decisive  as  to  this.  From 
the  moment  they  recover  their  sight,  they  experience  the 
same  visual  sensations  as  we  do.  But  their  eyes  have  not 
been  educated  like  ours ;  consequently,  what  is  then  want- 
ing to  their  eyes  is  what  ours  have  acquired  ;  the  missing 
parts  of  their  perception  afford  a  measure  of  the  additions 
which  have  gone  to  complete  our  perception. — Still,  for  the 
purpose  of  explaining  the  different  results  of  experience,  it 
is  necessary  first  to  determine  whether  the  education  of 
their  eyes  has  been  absolutely  nothing  or  only  amounting 
to  nothing.*  In  most  cases,  the  crystalline  lens,  though 


*  See  the  cases  recorded  by  Cheselden,   "  Philosophical  Transactions  "  for  the 
year  1728. — Ware,  ib.  1801. — Home  ib.  1807. — Wardrop,  ib.  1826. 


CHAP.  II]  THE  EDUCATION  OF  THE  SENSES.  307 

opaque,  still  permitted  the  passage  of  a  small  portion  of 
light ;  Cheselden's  patient  could  distinguish  three  colors, 
black,  white,  and  scarlet ;  Ware's  patient  could  distinguish 
strongly-marked  colors  when  held  close  to  his  eye.  Con- 
sequently, some  of  them  had  learned  to  direct  their  looks 
towards  an  object,  and  could  judge  to  a  certain  extent  of 
distance  by  the  colors  growing  feebler.  This  explains 
how,  in  certain  cases,  the  patient  was  able  immediately 
after  the  operation  to  take  hold  of  the  surgeon's  hand  and 
to  say,  by  sight  only,  whether  it  was  brought  nearer  to  or 
carried  further  from  him.  But  this  is  unusual,  and  when 
the  patient  has  not  learned  to  interpret  the  meaning  of  the 
color  growing  feebler,  he  has  no  idea  of  the  position  of 
visible  objects.  Usually,  at  the  moment  he  first  sees 
clearly,  he  imagines  "  that  all  the  objects  he  sees  touch  his 
eyes,  just  as  the  objects  he  feels  touch  his  skin."f  So  said 
the  patients  of  Cheselden  and  Home;  they  situated  their 
new  sensation  in  acordance  with  their  accustomed  sen- 
sations of  touch,  and  applied  their  former  experience  to 
the  new  instance.:}:  Besides  this,  Home's  patient  had 
always  done  so ;  before  the  operation,  when  he  looked  at 
the  sun  through  his  opaque  crystalline  lenses,  he  said  it 
appeared  to  touch  his  eye.  The  operation  performed,  the 
same  localizing  judgment  remained ;  when  asked,  soon  after, 
what  he  had  seen,  he  said :  "  Your  head,  which  seemed  to 
touch  my  eye,"  but  he  could  not  tell  its  shape.  It  was  not 
till  three  months  afterwards,  and  a  month  after  the  lowering 
of  the  second  cataract,  that  objects  did  not  seem  as  before  to 
touch  his  eyes,  but  appeared  to  be  at  a  short  distance  from 
him.  Not  one  of  the  blind  persons  so  operated  on  was  able 

\  In  a  case  reported  by  Mr.  Nunnely,  "  the  young  patient  said  that  the  objects 
touched  his  eyes,  and  walked  about  cautiously,  keeping  his  hands  raised  before 
his  eyes,  to  prevent  these  objects  from  touching  and  hurting  them." — J.  S.  Mill, 
"  Exam,  etc."  Third  edition,  p.  285, 

\  Before  the  operation  the  blind  person  has  opened  and  shut  his  eyelids,  and 
has  certainly  known  their  situation  as  that  of  other  parts  of  his  body.  Usually, 
when  the  operation  is  performed,  the  light  is  too  keen  for  his  eyes  and  compels 
him  to  close  them,  and  to  contract  the  pupil. — Here  are  two  muscular  sensations 
whose  situation  he  knows,  and  which  no  doubt  contribute  to  make  him  situate  his 
new  visual  sensation  against  his  eyeball. 


308  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

at  first  to  interpret  his  new  sensations,  to  decide  on  the  situ- 
ation, form,  and  magnitude  of  objects,  or  to  recognize  them. 
It  was  requisite  for  the  touch,  slowly  and  gradually,  to  in- 
struct the  eye.  Home's  second  patient  was  asked,  ten  min- 
utes after  the  operation,  the  shape  of  a  round  piece  of  card, 
and  said,  "  Let  me  touch  it,  and  I  will  tell  you."  He  was  not 
allowed  to  do  so,  and,  after  thinking  for  some  time,  said  it 
was  round.  But  a  moment  afterwards,  he  said  the  same 
thing  of  a  little  square  piece  of  card,  and  again  of  a  triangu- 
lar piece.  The  experiment  was  repeated  some  hours  after- 
wards. At  first  the  boy  called  the  different  cards  round  ;  but 
upon  being  shown  a  square,  and  asked  if  he  could  find  any 
corners  to  it,  he  was  very  desirous  of  touching  it.  This  be- 
ing refused,  he  examined  it  for  some  time,  and  said  at  last 
that  he  had  found  a  corner,  and  then  readily  counted  the  four 
corners  of  the  square.  Thus  commenced  the  first  education 
of  the  eye.  All  the  patients  resembled  Cheselden's,  who 
"  knew  not  the  shape  of  anything,  nor  any  one  thing  from  an- 
other, however  different  in  shape,  or  magnitude ;  but  upon 
being  told  what  things  were,  whose  form  he  before  knew  from 
feeling,  he  would  carefully  observe,  that  he  might  know  them 
again  ;  but  having  too  many  objects  to  learn  at  once,  he  for- 
got many  of  them  ;  and  (as  he  said)  at  first  he  learned  to  know, 

and  again  forgot  a  thousand  things  in  a  day Having 

often  forgot  which  was  the  cat,  and  which  the  dog,  he  was 
ashamed  to  ask ;  but  catching  the  cat  (which  he  knew  by 
feeling),  he  was  observed  to  look  at  her  steadfastly,  and  then 
setting  her  down,  said,  '  So,  puss  !  I  shall  know  you  another 
time.'  "  Later  on,  when  he  had  learned  to  know  his  parents 
by  sight,  "  being  shown  his  father's  picture  in  a  locket  at  his 
mother's  watch,  and  told  what  it  was,  he  acknowledged  a 
likeness,  but  was  vastly  surprised  ;  asking  how  it  could  be  that 
a  large  face  could  be  expressed  in  so  little  room,  saying,  '  It 
should  have  seemed  as  impossible  to  him,  as  to  put  a  bushel 
of  anything  into  a  pint.' "  * 


*  "  Caspar  Hauser,  in  a  detailed  account  of  his  own  experience  in  this  respect 
states,  that  upon  his  first  liberation  from  confinement,  whenever  he  looked  through 
the  window  upon  external  objects,  such  as  the  street,  garden,  etc.,  it  appeared  to 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  309 

They  require  time  to  reconcile  the  different  visual  sensa- 
tions which  the  same  object  presents  according  to  its  different 
distances,  and  to  reconcile  all  these  with  the  muscular  and 
tactile  sensations  with  which  the  object  has  already  furnished 
them.  The  most  instructive  case  in  this  respect  is  that  of 
the  lady  operated  on  by  Wardrop. — Her  blindness  was  more 
complete  than  that  of  the  others ;  for  not  only  was  she  born 
with  cataracts  in  each  eye,  but,  when  six  months  old,  an  un- 
skilful surgeon  had  destroyed  the  right  eye  and  closed  up  the 
pupil  of  the  left.  She  could  not  recognize  any  color,  she  was 
able  merely  to  distinguish  a  very  light  from  a  very  dark  room, 
but  without  having  the  power  to  perceive  even  the  situation 
of  the  window,  through  which  the  light  entered ;  though  in 
sunshine  or  in  bright  moonlight  she  knew  the  direction  from 
whence  the  light  emanated.  When  placed  under  Wardrop's 
care  she  had  reached  her  forty-sixth  year.  He  opened  the 
iris,  she  was  able  to  see,  and  "  returned  home  in  a  carriage, 
with  her  eye  covered  only  with  a  loose  piece  of  silk.  The 
first  thing  she  noticed  was  a  hackney- coach  passing,  when  she 
exclaimed,  '  What  is  that  large  thing  that  has  passed  by  us  ?  ' 
In  the  course  of  the  evening,  she  requested  her  brother  to 
show  her  his  watch  ....  and  looked  at  it  for  a  considerable 
time,  holding  it  close  to  her  eye.  She  was  asked  what  she 
saw;  and  she  said  there  was  a  dark  and  a  bright  side."  In 


him  as  if  there  were  a  shutter  quite  close  to  his  eye,  and  covered  with  confused 
colors  of  all  kinds,  in  which  he  could  recognize  or  distinguish  nothing  singly. 
He  says  farther,  that  he  did  not  convince  himself  till  after  some  time  during  his 
walks  out  of  doors,  that  what  had  at  first  appeared  to  him  as  a  shutter  of  various 
colors,  as  well  as  many  other  objects,  were  in  reality  very  different  things  ;  and 
that  at  length  the  shutter  disappeared,  and  he  saw  and  recognized  all  things  in 
their  just  proportions." — Franz,  "  On  the  eye,"  p.  34-6.  Dr.  Franz  adds  : — Since 
ideas  are  gained  by  reflection  upon  sensation,  it  is  further  necessary  in  all  cases  in 
order  that  an  accurate  idea  of  objects  may  be  formed  from  the  sense  of  sight,  that 
the  powers  of  the  mind  should  be  unimpaired  and  undisturbed  in  their  exercise. 
A  proof  of  this  is  afforded  in  the  instance  related  by  Haslam  ('  Observations  on 
Madness  and  Melancholy,' — Second  edition,  p.  192),  of  a  boy  who  had  no  defect 
of  sight,  but  was  weak  in  understanding,  and  who  in  his  seventh  year  was  unable 
to  estimate  the  distance  of  objects,  especially  as  to  height  ;  he  would  extend  his 
hand  frequently  to  a  nail  on  the  ceiling,  or  towards  the  moon,  to  catch  it.  It  is, 
therefore,  the  judgment  which  corrects  and  makes  clear  this  idea,  or  perception  of 
visible  objects." 


310  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

fact,  these  two  sensations  of  brightness  and  darkness  alone 
corresponded  to  her  former  sensations,  since  till  then  she 
had  never  been  able  to  do  more  than  distinguish  light  and 
darkness. — She  was  seen  hourly  to  observe  first  one  point, 
then  another,  then  again  others  in  the  numbers  of  sensations 
of  color  which  besieged  her.  But  she  was  bewildered  by 
them  ;  "  I  feel  stupid,"  she  said.  She  voluntarily  remained 
silent,  not  being  able  to  make  out  the  chaos  of  impressions 
which  were  as  yet  destitute  of  meaning  to  her  inexperienced 
eye. — A  fortnight  later,  she  still  said,  "  I  see  a  great  deal  if  I 
could  only  tell  what  I  do  see ;  but  surely  I  am  very  stupid." 
Nevertheless,  she  learned  by  degrees  the  names  of  colors,  and 
was  soon  able  to  distinguish  them ;  but  as  to  the  perception 
of  figures,  that  is  to  say  for  the  transcription  into  the  new 
visual  atlas  of  the  old  tactile  and  muscular  atlas,  the  appren- 
ticeship was  very  long. — On  the  seventh  day  she  was  exam- 
ining the  teacups  and  saucers,  and  was  asked,  "  What  are  they 
like  ? "  "I  don't  know,"  she  replied  ;  "  they  look  very  queer 
to  me,  but  I  can  tell  what  they  are  in  a  minute  when  I  touch 
them." — "She  distinguished  an  orange  on  the  chimney-piece 
but  could  form  no  notion  of  what  it  was  till  she  touched  it." 
On  the  eighteenth  day  the  experiment  was  made  "  of  giving 
her  a  silver  pencil-case  and  a  large  key  to  examine  with  her 
hands ;  she  discriminated  and  knew  each  distinctly ;  but 
when  they  were  placed  on  the  table  side  by  side,  though  she 
distinguished  each  with  her  eye,  yet  she  could  not  tell  which 
was  the  pencil-case,  and  which  the  key."  On  the  twenty-fifth 
day,  being  in  a  carriage  in  the  Regent's  Park,  she  inquired 
continually  as  to  the  meanings  of  her  visual  sensations,  such 
as — "  '  What  is  that  ?  '  '  It  is  a  soldier,'  she  was  answered. 
'  Who  is  that,  that  has  passed  us  just  now  ? '  It  was  a  person 
on  horseback.  '  But  what  is  that  on  the  pavement,  red  ? '  It 
was  some  ladies  who  wore  red  shawls." — It  was  constantly 
necessary  to  translate  for  her  into  the  language  of  touch, 
which  she  understood,  the  unknown  language  of  the  eye. — 
As,  before  the  operation,  she  knew  from  what  direction  the 
light  proceeded,  she  was  probably  already  capable  of  approx- 
imately directing  her  head  and  eyes  to  the  side  at  which  the 
illuminated  objects  appeared ;  but  even  this  art  was  entirely 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  311 

rudimentary.  On  the  eighteenth  day,  "  she  seemed  to  have 
the  greatest  difficulty  in  finding  out  the  distance  of  any  ob- 
ject ;  for  when  an  object  was  he.ld  close  to  her  eye,  she  would 
search  for  it  by  stretching  her  hand  far  beyond  its  position, 
while,  on  other  occasions,  she  groped  close  to  her  own  face 
for  a  thing  far  removed  from  her  .  .  .  ." — When  at  the  end 
of  six  weeks  she  left  London,  she  had  acquired  a  pretty  ac- 
curate knowledge  of  colors  and  their  different  shades  and 
names,  and  also  of  many  objects,  but  "  had  not  yet  acquired 
anything  like  an  accurate  knowledge  of  distance  or  of  forms, 
and  up  to  this  period  she  continued  to  be  very  much  confused 
with  every  object  at  which  she  looked.  Neither  was  she  able, 
without  considerable  difficulty  and  numerous  fruitless  trials, 
to  direct  her  eye  to  an  object ;  so  that  when  she  attempted 
to  look  at  anything,  she  turned  her  head  in  various  directions, 
until  her  eye  caught  the  object  of  which  it  was  in  search." 
In  fact  the  least  movement  of  the  head  changes  all  our  visual 
sensations  for  other  ones ;  a  precise  movement  is  required, 
neither  too  great,  nor  too  small ;  to  attain  a  preconceived 
visual  sensation,  we  must  direct  our  glance  correctly.  Just 
as  an  infant  does  not  distinguish  or  retain,  till  after  many 
trials,  the  precise  nature  and  exact  amount  of  the  effort  re- 
quired to  throw  a  stone  ten  paces  and  not  nine  or  eleven  ;  so 
was  this  lady  unable  to  distinguish  and  fix  in  her  memory, 
until  after  many  incessantly  corrected  attempts,  the  particular 
nature,  the  degree  of  intensity,  and  the  precise  duration  of 
the  muscular  sensation  which  her  neck  must  experience  in 
order  for  the  inclination  to  right  or  left ;  the  raising  or  lower- 
ing of  her  head,  and  so  of  her  eye,  to  be  three  degrees  and 
not  two,  four,  or  five. 

All  these  particulars  result  in  one  conclusion — our  pure 
visual  sensations  are  nothing  more  than  signs. — Experience 
alone  acquaints  us  with  their  meanings ;  in  other  words,  ex- 
perience alone  associates  with  each  of  them  the  image  of  the 
tactile  and  muscular  sensation  corresponding  to  it. — At  the 
present  day,  the  analysis  of  physiologists  and  physicists  has 
noted,  by  a  multitude  of  proofs  and  counter-proofs,  the  vari- 
ous stages  of  this  association.*  The  sensations  which  the  re- 

*  Hclmholtz,  "  Physiologische  Optik,"  797. 


312  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II 

tina  procures  us  are  those  of  different  colors,  and  of  different 
degrees  of  light  and  shade  ;  and  further,  as  it  is  a  sheaf  of  dis- 
tinct nervous  fibres,  each  of  its  fibres,  in  accordance  with  the 
general  law  of  the  nervous  system,  excites,  when  impressed, 
a  distinct  sensation.  In  these  three  respects,  and  in  these 
three  respects  alone,  can  we  distinguish  a  pure  visual  sensa- 
tion from  others  similar  in  kind,  and  this  is  the  first  layer  on 
which  will  be  established  later  on  the  whole  fabric  of  our  vis- 
ual perceptions. — In  this  state,  which  is  that  of  the  person 
born  blind  immediately  after  the  operation,  the  eye  has  the 
sensation  only  of  variously  colored  patches  more  or  less  clear 
or  obscure;  and,  in  a  whole  patch,  it  can  observe  some  dis- 
tinct portion,  but  simply,  as  a  partial  patch.f  Wardrop's  pa- 
tient, looking  at  a  watch,  on  the  evening  of  the  operation,  ob- 
served the  figure  12,  the  figure  6,  and  the  hands,  but  simply 
as  patches  upon  a  patch,  without  knowing  what  they  were. 
So  again,  on  the  third  day,  looking  at  her  brother's  face,  she 
distinguished  in  this  round  flesh-colored  patch,  a  special  patch 
produced  by  the  prominence  of  the  nose,  and  guessed,  in  fact, 
that  it  was  the  nose. — Painters  in  color  are  well  aware  of  this 

s 

state ;  they  revert  to  it ;  their  art  consists  in  seeing  their 
model  as  a  patch,  the  only  element  of  which  is  the  more  or 
less  diversified,  deadened,  vivid,  and  mingled  color.  At  this 
stage,  there  is  no  idea  of  the  distance  or  position  of  objects, 


f  With  respect  to  this,  it  is  curious  to  observe  very  young  children.  I  have 
lately  been  able  to  apply  and  verify  the  theory  in  the  case  of  a  little  girl  whom  I 
saw  every  day  from  her  birth.  It  is  certain  to  my  mind  that,  during  tne  first  two 
months,  the  surrounding  world  was  composed  for  her  of  sounds  and  patches  of 
color,  which  she  did  not  know  how  to  situate.  At  two  months  and  a  half,  she  evi- 
dently recognized  the  direction  of  certain  sounds  ;  for  instance,  hearing  her  grand- 
mother's voice,  she  turned  her  head  towards  her.  At  three  months  she  knew,  in 
some  cases,  how  to  direct  her  looks  by  turning  her  head  and  eyes  towards  the  ob- 
ject she  wished  to  see,  and  among  others,  to  my  face.  But  she  could  not  do  this 
with  every  object. — Plainly,  what  she  first  distinguished,  noted  in  her  memory,  and 
recognized,  were  sounds  and  faces.  In  fact,  among  the  hundreds  of  sounds  and 
colored  forms  which  impressed  her  senses  were  the  tones  of  five  or  six  voices,  and 
the  colored  forms  of  five  or  six  faces,  and  these,  being  the  most  frequently  repeated, 
intruded,  by  their  frequency  and  identity,  on  the  rest. — At  about  three  months  old, 
she  commenced  to  feel  about  with  her  hands,  to  move  her  arms  to  reach  objects, 
consequently,  to  associate  with  the  colored  patches  tactile  and  muscular  impres- 
sions of  distance  and  form. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  3^ 

except  that  an  induction  derived  from  touch  places  them  in 
contact  with  the  eye.  No  doubt,  at  this  stage,  an  object  may 
be  recognized  by  the  color,  vividness,  and  characters  of  its 
patch,  as  Wardrop's  patient  was  able  to  distinguish  the  grass 
from  the  water,  but  nothing  is  known  as  to  its  situation.  The 
second  layer  of  the  edifice  is  not  constructed ;  it  is  now  nec- 
essary to  add,  little  by  little,  to  pure  retinal  sensations,  auxil- 
iary and  additional  ones. 

The  sensations  so  added  are  those  of  the  muscles  of  the 
eye ;  for  the  form  and  position  of  the  eye  are  susceptible  of 
changes,  and  these  changes  are  the  effect  of  its  muscular  ap- 
pendages.— In  the  first  place,  we  adjust  the  eye  to  the  dis- 
tance of  the  object,  by  disposing  it  in  such  a  way  that  the  lu- 
minous image  falls  precisely  on  the  retina,  and  not  before  or 
behind  it ;  otherwise,  the  vision  is  not  distinct ;  to  effect  this, 
we  alter  the  curvature  of  the  crystalline  lens,  probably  by  con- 
tracting the  ciliary  muscle,  and  the  muscular  fibres  of  the  iris. 
— Besides  this,  when  we  look  at  an  object  with  both  eyes,  our 
two  eyes  converge  more  or  less,  according  as  the  object  is  at  a 
greater  or  less  distance.  Now  this  greater  or  less  convergence 
is  produced  by  the  greater  or  less  contraction  of  the  muscles 
which  move  the  eye.  Consequently,  according  to  the  greater 
or  less  distance  of  the  object,  we  have  a  particular  muscular 
sensation  of  the  eye. — On  the  other  hand,  according  as  the  ob- 
ject is  in  one  or  the  other  direction,  with  reference  to  our 
eye,  one  or  other  of  the  muscles  which  move  the  eye  is  more 
or  less  contracted,  in  order  to  turn  it  upwards  or  downwards, 
to  the  right  or  left ;  in  such  a  way  that  when  the  distance  re- 
mains the  same,  a  distinct  muscular  sensation  corresponds  to 
every  change  of  direction. — We  learn  to  observe  and  engrave 
on  our  memory  these  innumerable  distinct  muscular  sensa- 
tions of  our  eyes.  At  the  same  time,  and  by  means  of  touch, 
we  associate  some  one  of  them  with  a  certain  movement  of 
our  hand,  another  with  the  semi-extension  of  our  forearm, 
others  with  two,  three,  six,  ten,  twenty  strides  of  our  legs. 
Henceforward,  when  a  pure  visual  sensation  follows  some  par- 
ticular voluntary  muscular  sensation  of  the  eye,  this  compound 
calls  up  the  idea  of  some  particular  movement  of  the  hand, 
the  forearm,  or  the  arm,  of  some  particular  number  of  steps,  in 


314  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

short,  of  some  portion  of  the  tactile  and  muscular  atlas  which 
the  experience  of  our  limbs  has  constructed  within  us,  and 
by  which  the  person  born  blind  estimates  distance  and  deter- 
mines positions. — At  the  end  of  three  weeks,  the  lady  opera- 
ted on  by  Wardrop  was  able  to  recognize  a  grass-plot  by  the 
large  and  beautiful  green  patch  it  formed  in  her  field  of  vis- 
ion. But  she  had  not  yet  distinguished  and  observed  what 
muscular  sensation  of  her  eye  had  resulted  in  the  apparition 
of  this  green  patch,  and  above  all,  had  not  ascertained,  from 
the  nature  of  the  muscular  sensation,  the  number  and  direc- 
tion of  the  steps  which  would  be  required  to  lead  her  up  to 
the  grass-plot ;  so  that,  though  she  saw  it,  she  did  not  know 
where  it  was,  and  perhaps  extended  her  foot  to  find  out  wheth- 
er it  was  not  close  to  her. — To  us  who  have  noted  the  various 
muscular  sensations  of  our  eyes,  and  have  associated  them  to 
the  recollection  of  the  movements  of  our  limbs  "  the  feeling 
that  we  have  when  the  eyes  are  parallel  and  vision  distinct,  is 
associated  with  a  great  and  prolonged  effort  of  walking,  in 

other  words,  with  a  long  distance The  change 

from  an  inclination  of  the  eyes  of  30°  to  an  inclination  of  10° 
is  associated  with  a  given  sweep  of  the  arm,  carrying  the  hand 
forward  over  eight  inches  and  a  half."*  In  this  way,  muscu- 
lar sensations  of  the  eye  become  in  our  cases  signs,  each  of 
which  has  power,  when  produced,  to  call  up  with  it  the  image 
of  some  particular  muscular  movement  of  the  limbs,  in  other 
words,  the  precise  idea  of  a  certain  distance  measured  in  a 
certain  direction. 

To  these  auxiliaries  add  the  rest — I  mean  the  muscular 
sensations  of  the  neck  and  body  in  turning,  bending,  and  draw- 
ing back,  so  as  to  enable  the  retina  to  receive  a  distinct  lumi- 
nous image ;  these  are  so  many  complementary  signs  which, 
in  connection  with  the  first,  effect  the  determination  of  the 
direction  of  the  object  by  the  association  they  have  contracted 
with  the  image  of  some  special  movement  of  the  limbs  carried 
out  in  some  particular  direction. — The  reader  now  sees  how 
the  eye  is  capable  of  perceiving  the  figure  of  a  body.  The 
visible  figure  of  a  body  is  nothing  more  than  a  double  series 


*  Bain,  "  Senses  and  Intellect,"  2nd  edition,  374. 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  3! 5 

of  optical  sensations,  a  retinal  series  and  a  muscular  series, 
both  of  which  are  parallel  and  continuous,  and  are  experi- 
enced whenever  the  eye  follows  the  outline  and  runs  over 
the  illuminated  surface  of  a  body.  Experience  associates  to 
this  double  series  of  sensations  a  series  of  images,  that 
is  to  say,  images  of  the  tactile  and  muscular  sensations 
which  the  hand  would  experience  in  following  the  outline, 
and  feeling  the  surface  of  the  bodies. — Other  experiences 
teach  us  that,  according  to  the  distance,  this  double  opti- 
cal series  undergoes  regular  alteration,  without  the  other  se- 
ries being  altered ;  and  we  express  this  by  saying  that  the 
same  tangible  object  passes  regularly,  according  to  distance, 
through  an  infinite  series  of  visible  appearances ;  and  it  fol- 
lows from  this,  that  when  we  see  it  at  a  particular  distance, 
the  row  of  its  other  visible  appearances  is  ready  to  revive  in 
us,  and  to  take  up  a  position  in  the  mental  background. — I 
leave  further  explanation  to  treatises  on  optics  and  physiolo- 
gy,* in  which  will  be  found  the  enumeration  and  explanation 
of  all  optical  judgments  and  errors.  They  are  the  subject- 
matter  of  a  whole  science,  but  are  all  reduced  to  one  princi- 
ple. "  By  experience,"  says  Helmholtz,f  "  we  can  evidently 
learn  what  other  sensations  of  the  sight  or  other  senses,  an 
object  we  see  will  excite  in  us,  if  we  advance  our  eyes  or  body, 
if  we  look  at  the  object  from  different  directions,  if  we  feel  it, 
etc.  The  concept  of  all  these  possible  sensations  combined 
in  a  whole  is  our  representation  of  the  body ;  and,  when  it  is 
sustained  by  our  actual  sensations,  it  is  what  we  term  the  per- 
ception of  the  body It  includes  all  the  distinct  possible 

groups  of  sensations  which  the  body  when  looked  at,  touched, 
experimented  on  in  various  ways,  can  excite  in  us ;  these  are 
its  real  effective  contents ;  it  has  no  others,  and  these  con- 
tents may  undoubtedly  be  acquired  by  experience.  The  only 
physical  activity  required  for  this  purpose  is  the  constant 
and  reviving  association  of  the  two  representations,  which  were 
already  connected  together,  an  association  which  becomes 
the  more  solid  and  more  constrained  in  proportion  to  the 


*  See  the  admirable  work  of  Helmholtz ;  above  all  the  third  part,  "  Die  Lehre 
von  den  Gesichts-Wahrnehmungen."  \  Ibid.,  p.  798. 


316  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

number  of  times  the  two   representations  have  reappeared 
together." 

From  this,  we  understand  in  what  our  visual  atlas  consists. 
— There  is  a  square  mahogany  table  three  paces  from  me,  to 
the  right.  I  turn  my  eyes,  and  have,  through  the  retina,  a 
sensation  of  a  certain  somewhat  glistening  brown  patch  ;  and 
I  have  at  the  same  time,  by  means  of  the  accommodation  of 
the  crystalline  lens  and  the  contraction  of  the  muscles  which 
move  the  eye,  a  certain  muscular  sensation  which,  by  an  ac- 
quired correspondence,  calls  up  in  me  the  image  of  three 
paces,  taken  to  the  right. — My  eyes  follow  the  outline  of  the 
table,  in  other  words,  my  retina  experiences  in  succession  a 
continuous  series  of  impressions  in  proportion  as  the  lumin- 
ous rays  starting  from  the  sides  of  the  table  successively  im- 
pinge on  its  yellow  centre  ;  now,  in  the  meantime,  the  accom- 
modation and  contraction  of  the  muscles  of  the  eye  give  me 
a  parallel  and  continuous  series  of  muscular  sensations,  which, 
by  an  acquired  correspondence,  call  up  in  me  the  images  of 
the  tactile  and  muscular  sensations  which  my  hand  would 
experience  in  passing  over  its  side  from  corner  to  corner. — 
Let  us  remark  the  character  of  these  re-excited  images.  If 
my  glance  has  been  a  rapid  one,  they  are  not  express  ;  they 
remain  in  the  nascent  state ;  I  am  compelled  to  prolong  my 
glance  to  call  them  up  precisely  and  completely,  to  imagine 
the  muscular  sensations  of  my  three  steps,  the  muscular  and 
tactile  sensations  of  my  hand,  passed  along  the  edge  of  the 
table.  I  only  get  at  this  by  dwelling  on  it,  by  silently  in- 
quiring of  myself  what  it  is  I  mean  by  this  distance  and  this 
form.  Even  when  dwelling  on  it,  I  commence  by  imagining 
the  first  step  I  should  take,  the  sensation  which  my  hand 
would  receive  from  the  first  corner ;  these  two  images  serve 
as  type  for  the  rest.  In  fact,  my  operation  is  the  same  as 
when  in  a  written  sentence  I  read  the  word  tree ;  if  I  read  it 
rapidly,  I  simply  understand  it ;  it  does  not  call  up  express 
images  in  my  mind  ;  it  is  necessary  to  weigh  it,  to  reflect,  in 
order  to  cause  the  image  of  a  beech,  an  apple,  or  other  tree 
to  appear ;  even  then,  it  will  be  vague  and  mutilated ;  at  the 
most,  I  shall  get  a  view  of  some  lineaments  of  a  colored  form, 
the  obliterated  sketch  of  a  green  dome  or  pyramid ;  it  will 


CHAP.  II.]  THE  EDUCATION  OF  THE  SENSES.  317 

only  be  by  dwelling  strongly  on  it  for  some  time  that  I  shall 
cause  images  of  trees  to  spring  up  sufficiently  clear  and 
numerous  to  be  equivalent  to  the  generic  word  which  sums 
up  and  denotes  them  all. — Thus  our  optical  sensations  are, 
like  our  words,  signs.  Every  retinal  and  muscular  sensation 
has,  like  every  word,  its  group  of  associated  images  ;  it  rep- 
resents this  group ;  it  replaces  and  denotes  it ;  in  other 
words,  it  is  always  associated  with  it,  and  never  otherwise 
associated,  so  that  in  use  and  practice  it  is  equivalent  to  it. 
In  fact,  when  the  sensation  arises,  the  group  is  at  hand,  ready 
to  revive.  Give  it  a  little  time,  and  it  will  partially  revive. 
Give  it  enough  time,  and  it  will  wholly  revive.  It  forms  part 
of  the  train  of  the  sensation  ;  but,  as  the  operations  are  rapid, 
it  most  usually  remains  in  the  background ;  the  sensation 
alone  occupies  the  stage.  As  the  sensation  is  there  for  an 
instant  only,  and  the  train  requires  time  to  pass  in  proces- 
sion, the  train  remains  behind  the  scenes. — We  know  some- 
thing of  this  world  behind  the  scenes.*  The  reader  had  a 
view  of  it  when  we  pointed  out  the  silent  persistence  of 
images,  their  latent  existence,  their  rudimentary  state,  the 
obliteration  they  undergo,  and  the  life  they  preserve,  often 
for  whole  years,  until  the  indistinct  vibration,  which  was  per- 
petuated in  some  only  of  the  cells  of  the  hemispheres, 
receives  from  some  unforeseen  circumstance  a  universal  as- 
cendancy, and  becomes  suddenly  propagated  through  the 
majority  of  the  chords  of  the  cerebral  instrument. 

The  better  to  comprehend  their  obliteration  and  the  part 
they  still  play,  though  in  this  latent  state,  let  us  consider 
greater  distances,  and  generally,  the  process  by  which  d  istances 
are  estimated. — In  a  geographical  map  we  look  at  the  myria- 
metre  traced  at  the  foot,  and  applying  compasses  to  this 
myriametre,  we  pass  about  the  map,  measuring  in  this  man- 
ner if  Paris  is  farther  from  Bourges  than  from  Tours  or  Dun- 
kirk.— At  the  outset  of  the  operation  we  estimated  the 
myriametre  in  muscular  sensations,  and  found  it  equivalent 
to  some  walk  we  have  been  accustomed  to  take,  to  12,000 
paces,  to  two  hours'  walking.  But,  soon  after,  we  forgot  the 


*  See  part  i.  book  iv.  chap  i.  pp.  178-80. 


318  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

muscular  signification  we  attached  to  this  expansion  of  the 
compasses ;  we  left  it  behind  us,  in  reserve  ;  all  we  kept  in 
mind  was  degree  of  expansion  and  its  multiples ;  we  di- 
rectly compared  a  series  of  expansions  to  a  series  of  expan- 
sions, a  series  of  greater  ones  to  a  series  of  less.  We  follow 
the  same  process  in  all  our  estimations  of  quantities,  and  the 
spontaneous  operations  of  our  eye  do  but  precede  the  artifi- 
cial operations  of  our  instruments. — In  the  first  stages  of  our 
observation,  as  at  the  limit  of  our  science,  we  prove  a  constant 
relation  between  two  quantities,  just  now  between  our  more 
or  less  numerous  steps  and  the  greater  or  less  expansions  of 
the  compasses,  at  present  between  the  more  or  less  long  and 
repeated  muscular  sensations  of  our  limbs,  and  the  muscular 
sensations  which  we  receive  from  the  greater  or  less  conver- 
gence of  our  eyes,  the  greater  or  less  flattening  of  the  crystal- 
line lens,  the  greater  or  less  contraction  of  some  one  of  the 
muscles  which  move  the  eyes,  the  greater  or  less  movement 
of  our  body  and  head  in  some  particular  direction.  The  sec- 
ond quantity  increases  or  decreases  with  the  first,  according 
to  a  fixed  law. — This  being  settled,  we  take  a  standard  of  the 
second,  just  now  a  certain  expansion  of  the  compasses,  for  in- 
stance the  expansion  which  measures  the  myriametre,  now  a 
certain  muscular  sensation  of  our  optical  apparatus,  for  in- 
stance, the  muscular  sensation  which  the  eye  must  experience 
in  order  to  have  the  retinal  sensation  of  an  object  situated  at 
thirty  centimetres  distance.  At  this  moment,  too,  the  stand- 
ard and  its  signification,  that  is  to  say  the  expansion  of  the 
compasses  and  the  recollection  of  our  walk,  that  is  to  say 
again,  the  muscular  sensation  of  the  eye  and  the  image  of  the 
muscular  sensation  of  the  arm  carried  thirty  centimetres  for- 
ward, are  together  in  our  mind.  But  a  moment  afterwards 
the  standard  alone  remains  ;  the  image  or  the  recollection  to 
which  it  is  equivalent  becomes  thin,  and  fades  away ;  we  sim- 
ply observe  that  a  certain  expansion  is  greater  than  another, 
that  a  certain  muscular  sensation  of  the  eye  is  stronger  and 
more  prolonged  than  another;  we  no  longer  perceive  the  sig- 
nified quantities  but  only  the  significant  ones. — This  is  enough ; 
for,  by  means  of  the  indicated  association,  the  signified  quan- 
tities remain  within  call,  and  their  proximity  is  as  good  as 


CHAP.  II.]          THE  EDUCATION  OF   THE   SENSES. 

their  presence.  At  any  moment  we  can  recall  them,  can  ob- 
serve that  a  certain  expansion  of  the  compasses,  that  is  to 
say  one  of  three  times  the  extent  of  the  first,  would  require 
of  us  three  times  as  many  steps,  or  six  hours'  walking,  that  a 
smaller  muscular  sensation  of  the  eye  would  require  a  double 
extension  of  our  arm. — We  know  how  a  map  serves  us  on  a 
walking  tour ;  by  applying  to  it  compasses  we  foresee  the 
length  of  our  walks,  and  the  amount  of  muscular  effort  we 
shall  be  compelled  to  expend.  Our  visual  atlas  is  of  the  same 
use  ;  by  translating  certain  of  its  indications  into  the  corre- 
sponding indications  of  the  tactile  and  muscular  atlas,  we 
foresee  the  distance,  the  magnitude  and  duration  of  the  mus- 
cular effort  by  which  our  limbs  will  reach  some  particular  ob- 
ject. 

VI.  We  see  now  how  it  is  that  a  visual  sensation,  so  short 
as  to  appear  instantaneous,  can  give  us  the  idea  of  very  di- 
versified and  very  great  extension.  This  arises  from  its  being 
equivalent  to  the  very  diversified  and  very  long  tactile  and 
muscular  sensations  by  which  we  should  perceive  this  exten- 
sion. It  sums  them  up,  and  so  becomes  their  substitute,  and 
signifies  them  while  replacing  them. 

But,  even  were  we  incapable  of  having  this  sensation,  we 
should  still  contrive  to  represent  to  ourselves  in  combination, 
and  as  simultaneous,  a  great  number  of  the  parts  of  space. — I 
have  questioned  many  blind  persons  as  to  this,*  their  answer 
is  unanimous,  wholly  precise  and  decided.  No  doubt  the 
perception  of  a  new  object  requires  more  time  in  their  cases 
than  in  ours,  since  they  are  compelled  to  explore  it  in  detail 
by  touch.  But,  having  done  so,  they  think  of  the  object, 
whatever  it  be,  a  sphere,  a  circle,  or  even  a  considerable  space, 
for  instance,  a  street,  all  at  once,  and  represent  it  to  themselves 
in  mass.  "All  there  is  wanting  to  us,"  they  say,  "is  what 
you  call  the  idea  of  color ;  the  object  is  to  us  just  what  an  un- 
shaded drawing  or  photograph  is  to  you,  speaking  more  pre- 
cisely, a  combination  of  lines.  We  conceive  a  whole  group  of 
diverging  or  intercrossing  lines  simultaneously,  and  that  is  to 


*  At  the  Institut  des  Jeunes-Aveugles  at  Paris,  thanks  to  the  kindness  of  the 
Professors  and  Director  of  the  establishment. 


320  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

us  figure."  Above  all,  they  expressly  deny  that  in  order  to 
imagine  a  line  or  a  surface,  they  require  to  represent  to  them- 
selves the  successive  sensations  of  their  hand  passed  in  some 
particular  direction.  "  That  would  be  too  long,  and  we  have 
no  need  whatever  to  think  of  our  hand :  it  is  but  an  instru- 
ment of  perception  of  which,  after  perception,  we  cease  to 
think." 

In  fact,  if,  at  the  origin  of  the  idea  of  distance,  we  find  a 
longer  or  shorter  series  of  muscular  sensations  of  the  arm  or  leg, 
it  is  at  the  origin  only.  It  matters  little  whether  these  sensa- 
tions appertain  to  one  limb  or  the  other,  whether  they  are 
muscular  or  not ;  this  is  but  a  detail  and  an  accessory  ;  it  is 
obliterated,  we  cease  to  attend  to  it.  We  leave  aside,  as  the 
blind  say,  all  the  circumstances  and  intrinsic  qualities  of  our 
sensations ;  we  preserve  only  the  essential  part,  and  the  essen- 
tial part  here,  is  that  they  form  a  series  interposed  between 
the  two  points  whose  distance  we  are  estimating.  Taken 
thus  abstractedly,  these  sensations  become,  as  it  were,  uncol- 
ored  and  neutral ;  they  are  any  sensations  whatever ;  we  con- 
sider them  not  as  to  their  quality  but  as  to  their  quantity ;  what 
we  observe  in  them  is  the  greater  or  less  duration  of  their  series : 
nothing  more.  Henceforward,  we  are  able  to  imagine  them 
with  great  promptitude,  and  to  compare  series  to  series.  Such 
is  the  process  employed  by  a  person  born  blind  ;  he  may,  like 
Saunderson,  become  a  geometrician,  may  conceive  longer  or 
shorter  series,  diverging  according  to  such  and  such  an  angle ; 
these  are  lines,  and,  by  a  combination  of  such  lines,  he  con- 
ceives geometrical  bodies.  For  our  own  parts,  we  avail  our- 
selves of  this  process  when  we  define  lines  by  the  motion  of 
a  point,  the  surface  by  the  motion  of  a  line,  the  solid  by  the 
motion  of  a  surface,  and  when  we  estimate  a  line,  a  surface, 
or  a  solid  by  the  greater  or  less  prolongation  of  the  muscular 
operation,  which  engenders  its  perception.  Now  we  can  im- 
agine these  movements  with  extreme  rapidity ;  we  may,  then, 
thus,  by  these  means  alone  conceive  many  lines,  therefore  a 
surface,  and  even  an  entire  solid,  almost  in  an  instant. 

But,  fortunately,  we  have  a  second  aid,  the  visual  atlas, 
which  is  added  in  our  cases  to  the  tactile  and  muscular  atlas. 
Thanks  to  it,  we  have  at  our  disposal  new  series  which  may 


CHAP.  II.]          THE  EDUCATION  OF   THE   SENSES.  321 

be  compared  together,  and  whose  elements  succeed  in  us  with 
prodigious  velocity.  These  are  the  little  muscular  sensations 
of  the  eye,  which  are  extremely  short,  and  able,  therefore, 
to  denote,  in  an  imperceptible  portion  of  time,  very  great 
distances,  and  positions  as  numerous  as  various.  They  take 
the  place  of  the  muscular  and  tactile  images  corresponding  to 
them,  and,  as  they  pass  in  a  moment,  it  seems  as  if  the  much 
longer  series  of  tactile  and  muscular  sensations  has  also  taken 
effect  in  a  moment.  Their  muscular  and  tactile  signification 
springs  up  with  them,  and  we  imagine  that  we  perceive  at  once 
a  number  of  distant  and  co-existing  points. — The  reader  has 
already  met  with  many  operations  of  this  kind  ;  it  is  what 
happens  with  all  abbreviatory  substitutes.  The  muscular 
sensations  of  the  eye  serve  us  in  sight  as  words  do  in  abstract 
reasoning.*  When  I  contemplate  the  different  views  of  an 
extensive  landscape,  these  sensations  alone  are  in  my  mind, 
just  as,  when  I  read  a  chapter  on  political  economy  or  moral 
philosophy,  there  are  words  alone  in  my  mind,  and  yet,  in  the 
first  case,  I  believe  that  I  directly  perceive  magnitudes  and 
distances,  as,  in  the  second  case,  I  believe  that  I  directly  per- 
ceive pure  qualities  and  general  relations. — To  employ  the 
expressions  of  Mr.  Herbert  Spencer,  these  little  simultaneous 
or  nearly  simultaneous  muscular  sensations  are  to  us  "  symbols 
of  other  tactile  and  muscular  sensations,  which  were  slowly 
successive.  This  symbolic  relation,  being  far  briefer,  is  habit- 
ually thought  of  in  place  of  that  it  symbolizes :  and  by  the 
continued  use  of  such  symbols  and  the  union  of  them  with 
more  complex  ones,  are  generated  our  ideas  of  visible  exten- 
sion— ideas  which,  like  those  of  the  algebraist  working  out  an 
equation  are  wholly  unlike  the  ideas  symbolized ;  and  which 
yet,  like  his,  occupy  the  mind  to  the  entire  exclusion  of  the 
ideas  symbolized. "f — Hence  it  follows  that,  in  our  present 
state,  during  the  working  of  the  optical  substitutes,  the  image 
of  the  long  muscular  and  tactile  sensations  they  replace  must 
be  absent.  Consequently,  we  do  not  now  find  it  within  us, 
even  if  we  look  for  it ;  our  perception  of  visible  extension  will 
no  longer  comprise  any  of  the  muscular  and  tactile  sensations 

*  See  part  i.  book  i.  chap.  ii. 
f  "  Principles  of  Psychology,"  first  edition,  p.  224. 

ai 


322 


THE  KNOWLEDGE   OF  BODIES.  \EooK  II. 


of  the  limbs  and  hand.  Such  is,  in  fact,  the  conception  we 
now  have  of  visible  extension ;  in  this  state,  we  no  longer  find 
any  thing  in  it  to  recall  its  origin.  In  truth,  what  is  now  with- 
in us  is  not  the  image  of  the  original  successive  sensations  of 
the  hand  and  limbs,  but  their  optical  sign.  The  visual  atlas, 
constructed  by  means  of  the  muscular  and  tactile  atlas,  is 
wholly  different,  from  it ;  it  is  not  a  copy,  but  a  reproduction  on 
another  scale,  with  other  notations,  far  more  convenient  for 
use,  comprising  in  one  chart  what  is  dispersed  in  the  other  atlas 
over  twenty  several  maps,  and  presenting,  at  one  glance,  a 
group  so  vast  that,  in  the  other  atlas,  we  should  be  obliged  to 
arrive  at  it,  discursively  and  slowly,  over  twenty  different  leaves. 
This  visual  atlas  has  such  great  advantages  over  the  other 
that  we  constantly,  and  almost  exclusively,  employ  it. — In 
the  first  place  it  is,  as  we  have  seen,  extremely  abbreviatory 
for  all  distances  of  any  magnitude.  In  an  instant,  by  a  sim- 
ple diminution  of  the  convergence  of  the  eyes,  we  pronounce 
that  one  object  is  twenty  paces  further  from  us  than  another. 
In  an  instant,  by  a  simple  continuous  movement  of  the  eye, 
we  pronounce  that  a  particular  surface  is  square  or  triangular. 
This  frees  us  from  the  necessity  of  imagining  in  detail  the 
long  muscular  sensation  of  twenty  steps,  the  long  tactile  mus- 
cular sensation  of  the  hand  passed  over  the  whole  outline  of 
the  surface. — Thanks  to  this  rapidity  of  optical  operations,  we 
can  seize  in  a  very  short  time,  and  by. a  perception  which  ap- 
pears instantaneous,  a  whole  entire  object,  a  chair,  a  table,  a 
person,  and  more,  if  the  object  be  distant,  a  whole  meadow, 
a  group  of  trees,  a  building,  the  facade  of  a  street. — You  are 
placed  at  a  window,  you  open  your  eyes,  and  at  once,  by 
means  of  a  very  small  movement  of  the  eyes  and  an  imper- 
ceptible movement  of  the  head,  the  whole  landscape  appears 
to  you,  with  its  different  levels,  meadows,  woods,  sky,  clouds, 
with  their  innumerable  details  of  form,  relief,  and  shade.  Your 
eye  is  at  the  converging  point  of  the  luminous  rays  which 
start  from  the  objects — that  is  to  say  at  the  angle  of  the  com- 
passes formed  by  two  divergent  rays,  as  they  reach  the  retina. 
Now,  a  very  trifling  distance,  measured  near  the  angle  of  the 
compasses,  corresponds  to  an  immense,  and  sometimes  enor- 
mous distance  measured  at  their  points.  This  is  how  we  es- 


CHAP.  II.]  THE  EDUCATION  OF  THE   SENSES.  323 

timate,  at  a  glance,  hundreds  of  metres,  and  sometimes  of 
leagues ;  it  seems  to  us  at  the  time  that  all  the  sensations 
we  had  during  this  glance  are  simultaneous,  and  in  this  man- 
ner, all  the  external  objects  they  reveal  to  us  are  perceived, 
so  to  speak,  together ;  which  renders  far  easier  for  us  the  task 
of  recalling  and  comparing  them;  in  short,  of  practising  on 
them  the  various  ulterior  operations  of  which  we  have  need. 

On  the  other  hand,  very  small  distances  and  very  minute 
objects  are  also  within  the  province  of  sight.  In  this  respect 
the  skin,  compared  with  the  retina,  is  a  coarse  instr-ument, 
even  at  the  places  in  which  its  sensibility  is  most  delicate. — 
At  the  dorsal  vertebrae,  at  the  middle  of  the  arm,  of  the  thigh, 
of  the  neck,  when  two  adjacent  points  are  touched,  we  do 
not  distinguish  them  as  being  two,  unless  they  are  from  six- 
teen to  twenty-four  lines  apart ;  at  the  palmar  surface  of  the 
last  joints  of  the  fingers,  it  is  sufficient  for  the  points  to  be 
seven-tenths  of  a  line  apart ;  at  the  point  of  the  tongue,  where 
the  power  of  discrimination  is  most  perfect,  a  little  less  than 
half  a  line  is  a  sufficient  distance.* — On  the  contrary,  accord- 
ing to  Weber  and  Volkmann,  on  the  yellow  spot,  which  is 
the  most  sensitive  point  of  the  retina,  two  brilliant  specks 
may  be  distinguished  when  separated  only  by  an  interval  of 
from  .002  to  .001  of  a  line. — In  this  way,  the  retina  is  a 
thousand  or  two  thousand  times  as  sensitive  as  the  most 
sensitive  organ  of  touch. — Add  to  this  advantage  the  indica- 
tions afforded  by  color.  A  level  surface  for  instance,  a  printed 
or  written  page,  affords  one  uniform  sensation  only  to  touch, 
and  the  same  surface  affords  to  the  sight  as  many  distinct 
sensations  as  there  are  black  letters  written  or  printed  on  the 
white  ground.  So  the  tactile  and  muscular  atlas  does  not 
comprise  images  corresponding  to  very  minute  objects,  to  the 
form  and  proximity  of  two  threads  in  a  piece  of  fine  muslin, 
nor  images  corresponding  to  the  diversity  of  colored  surfaces, 
to  the  presence,  form,  and  movement  of  the  various  objects 
placed  beyond  the  reach  of  our  hand,  like  the  clouds,  the 
sky,  and  the  stars ;  primitively,  at  least,  these  images  were 
all  absent  from  the  tactile  and  muscular  atlas ;  if  they  have 


*See  the  complete  Table,  Mueller,  "Physiology"  (tr.  Baly),  i.  701. 


324  THE  KNOWLEDGE   OF  BODIES.  [Boon  II 

found  an  entrance,  it  has  been  but  subsequently  and  approx- 
imately, by  means  of  the  reciprocal  translation  which  we  are 
able  to  establish  between  the  two  atlases. 

We  need  not  be  surprised,  then,  at  the  enormous  part 
played  by  the  visual  atlas  in  ordinary  life.  For  our  parts,  to 
recollect,  to  imagine,  to  think,  is  to  see  internally ;  and  to  call 
up  the  more  or  less  enfeebled  and  transformed  visual  image 
of  things.  So,  too,  the  word  image  is  borrowed  from  the 
history  of  vision ;  strictly,  it  only  denotes  the  cerebral  revival  of 
the  optical  sensation  ;  it  is  by  extension  that  we  have  applied 
the  same  name  to  the  cerebral  revival  of  muscular  and  tactile 
sensations,  of  sensations  of  sound,  taste,  and  smell. — By  the 
same  encroachment  the  visual  atlas,  being  infinitely  more 
extended  and  much  more  readily  dealt  with  than  the  other, 
becomes  our  general  resort ;  all  our  sensations  are  transcribed 
into  it,  and  find  a  place  in  it,  the  muscular  and  tactile  ones 
with  the  rest.  In  fact,  I  have  internally  the  visual  represen- 
tation of  my  body,  and  even  of  the  parts,  like  the  back,  which 
I  have  not  seen  ;  and  when  I  contract  a  muscle,  or  undergo 
a  contact,  I  localize  the  contraction  and  contact,  not  only  by 
imagining  the  longer  or  shorter  sensation,  which  would  con- 
duct my  hand  as  far  as  the  spot  of  contraction  and  contact, 
but,  further,  and  above  all,  by  imagining  the  visual  form  and 
color  of  the  part  affected.  "  It  is  on  the  right  side,  at  the 
crown  of  the  head,  on  the  knee,  between  the  bones  of  the 
left  elbow."  When  we  mentally  pronounce  a  judgment  like 
this,  we  mentally  see  the  colored  form  of  the  parts. — This 
extends  so  far  that,  usually,  in  order  to  represent  to  ourselves 
the  movement  of  the  arm  which  would  be  required  to  meas- 
ure a  distance,  we  make  use,  not  of  muscular  images,  but  of 
visual  images,  and  represent  to  ourselves,  not  the  prolonged 
contraction  of  our  arm,  but  the  colored  form  of  our  arm 
passed  through  the  air  from  one  visible  point  to  another. — 
And  so,  to  estimate  the  distance  of  a  sound,  AVC  represent  to 
ourselves  by  visual  images  the  space  which  surrounds  us,  and 
situate  the  sonorous  trembling  at  a  particular  height,  in  a 
particular  direction,  at  a  particular  point  of  distance  or  prox- 
imity, in  the  huge  field  surrounding  our  body  and  traversed 
by  the  glance  of  the  external  or  the  internal  eye. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES.  325 

As  to  sensations  of  taste  and  smell,  the  two  atlases  come 
at  once  into  play,  in  order  to  situate  them ;  we  have  the  vis- 
ual representation,  as  well  as  the  tactile  and  muscular  repre- 
sentation of  our  nose  and  mouth.  In  fact,  as  to  the  inside  of 
the  mouth,  it  is  the  second  representation  which  is  of  most 
service,  since  the  tongue  plays  the  part  of  the  hand  ;  for  in- 
stance, we  discern  and  imagine  by  tactile  and  muscular  sen- 
sations only  the  movements  which  we  must  make  to  emit  the 
various  sounds  and  articulations  of  language.  Here,  sight 
and  visual  sensations  do  not  intervene ;  it  is  later  on,  by  the 
aid  of  physiology,  that  our  eye  takes  account  of  the  tongue, 
and  other  appendages  which  modify  the  sound  proceeding 
from  our  larynx,*  it  is  then  only  that  we  can  visually  imagine 
the  pronunciation  of  a  guttural  or  dental. — And  so,  too,  the 
tactile  and  muscular  atlas  is  solely,  or  almost  solely,  employed 
to  note  the  short  movements  of  the  trunk  on  its  base,  and 
sometimes  all  the  movements  of  walking  ;  for  instance,  when 
we  mount,  in  the  dark,  a  staircase  with  which  we  are  not  ac- 
quainted, all  that  we  imagine  is  the  regular  recurrence  of  the 
same  tactile  and  muscular  sensations  ;  the  visual  atlas  of  the 
staircase  is  wholly  wanting,  and  the  visual  atlas  of  our  legs 
and  body  is  almost  absent. — These  are  remnants  or  revivals 
of  its  primitive  predominance  ;  in  such  cases,  we  situate  our 
sensations  somewhat  in  the  fashion  of  persons  born  blind  ;  but 
here  we  have  fragments  only. 

In  fact,  not  only  is  the  visual  atlas  almost  entirely  substi- 
tuted for  its  rival,  but,  further  than  this,  it  has  hindered  its 
rival  from  acquiring  all  the  perfection  of  which  it  is  capable. 
Evidently,  at  present,  as  to  muscular  and  tactile  sensations, 
we  have  rough  discrimination  only ;  we  can  hardly  distin- 
guish their  shades  of  difference,  for  want  of  being  compelled 
to  do  so.  Platner  observed  that  the  blind  man,  whose  case 
he  described,  was  far  more  skilful  than  we  are  in  this  respect, 
and  this  is  true  of  all  blind  persons  ;  with  some  of  them  the 
perfection  of  the  sense  of  touch  surpasses  all  imagination. 
"  Saunderson,  the  blind  mathematician,"  says  Abercrombie,f 

*  This  accounts  for  M.  Jourdain's  astonishment  when  he  learned  that,  to  say 
U,  it  was  requisite  to  make  a  face, 
f  "Inquiry,"  etc.  p.  51. 


326  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II 

"  could  distinguish,  by  his  hand,  in  a  series  of  Roman  medals, 
the  true  from  the  counterfeit." — "  Mention  is  made,"  says 
Bayle,f  "  of  a  blind  organist  who  was  very  skilful  in  his  pro- 
fession, and  who  could  readily  distinguish  all  kinds  of  money 
and  colors.  He  even  played  at  cards,  and  was  very  fortunate, 
especially  when  it  was  his  turn  to  deal,  since  he  could  recog- 
nise by  touch  the  cards  he  gave  each  player.:}:  Aldrovandus 
says  that  a  certain  Jean  Ganibasius,  of  Volterra,  an  able  sculp- 
tor, having  lost  his  sight  at  the  age  of  twenty,  determined  ten 
years  after  to  attempt  what  he  could  in  the  way  of  his  pro- 
fession. He  felt  over  very  carefully  a  marble  statue  of  Cosmo 
I.,  Grand  Duke  of  Tuscany,  and  modelled  from  it  a  plaster 
one,  which  resembled  Cosmo  so  much  as  to  astonish  every- 
body. The  Grand  Duke  Ferdinand  sent  him  to  Rome,  where 
he  made  a  plaster  statue  resembling  perfectly  Urban  VIII." 
—Joseph  Kleinhaus,  who  died  at  Nauders  (Tyrol)  on  the 
loth  July,  1853,  had  become  blind  with  small-pox  at  five 
years  old.  He  at  first  amused  himself  by  carving  wood  to 
pass  the  time,  then  obtained  lessons  and  models  from  Prugg ; 
at  twelve  years  old  he  carved  a  crucifix  the  size  of  life,  and 
became  a  pupil  of  the  sculptor  Nissl,  improved  greatly  and 
became  celebrated.  He  is  computed  to  have  carved  four  hun- 
dred crucifixes,  and  a  bust  of  the  Emperor  Francis  Joseph. § 
— It  is  enough  to  see  blind  men  read  with  their  fingers  books 
printed  in  relief  almost  as  rapidly  as  we  read  books  printed  in 
black  and  white,  to  comprehend  all  the  power  of  discrimina- 
tion which  our  touch  might  have,  but  has  not,  acquired.* — 

f  Bayle,  cited  by  Gamier,  "  Traite  des  Facultes  de  1'ame,"  i.  354. 

\  If  this  be  true,  it  must  be  owing  to  the  painting  on  cards  having  differences 
of  grain  and  relief  corresponding  to  the  different  colors. 

§  Schopenhauer,  "  Les  quatre  racines  du  principe  du  raison  suffisante,"  p.  61. 

*  "  An  analogous  fact  is  observed  in  the  habit  acquired  by  the  deaf  and  dumb, 
of  understanding  what  is  said  to  them  by  watching  the  motion  of  the  lips  of  the 
speaker." — Abercrombie,  "  Inquiry,"  etc.  53. 

I  can  myself  mention  a  young  man  who  became  deaf  when  about  four  years  old, 
and  who,  having  very  good  eyesight,  saia  a  conversation  at  a  distance,  which  was 
inconvenient  enough  for  persons  who  were  whispering  privately  in  a  corner  at  the 
other  end  of  the  room.  He  could  thus  understand  German  and  French,  by  the 
movement  of  the  lips.  Only  it  was  necessary  that  the  conversation  should  not  con- 
tain many  proper  names  which  he  was  not  acquainted  with  ;  for  the  visible  .move- 
ment of  the  lips  showed  him  the  consonants,  and  not  the  vowels. 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  327 

Thus,  in  our  cases,  the  tactile  and  muscular  atlas  has  re- 
mained in  a  rudimentary  state.  This  is  why  when  we  at  pres- 
ent situate  one  of  our  sensations  of  touch,  of  sound,  of  smell, 
of  taste,  it  is  almost  always  through  the  visual  atlas  .alone,  or 
with  its  supplementary  concurrence  ;  in  other  words,  the  im- 
age of  an  optical  sensation  is  now  incorporated  with  sensations 
which  do  not  reach  us  by  the  eyes,  and  it  is  this  agglutination 
which  situates  them  in  the  places  in  which  they  appear  to  us. 
VII.  Here,  then,  are  all  our  sensations  situated,  that  is  to 
say  provided  with  an  apparent  position  and  seat,  all,  primi- 
tively, by  the  adjunction  of  a  series  of  muscular  images,  de- 
termining the  position,  and,  by  the  adjunction  of  a  series  of 
tactile  images  characterizing  the  seat,  almost  all,  finally,  by 
the  adjunction  of  visual  images,  which  have  become  equiva- 
lents of  this  series  and  signs  of  this  group. — We  are  now  able 
to  explain  our  present  conception  of  extension.  Suppose  a 
great  number  of  these  localized  sensations  to  be  simultane- 
ously produced,  and  the  points  to  which  we  refer  them  to 

The  hearing  and  other  senses  are  capable  of  acquiring  an  equal  delicacy. — 
"  Dr.  Rush  relates  of  two  blind  young  men,  brothers,  of  the  city  of  Philadelphia, 
that  they  knew  when  they  approached  a  post  in  walking  across  a  street,  by  a  pecu- 
liar sound  which  the  ground  under  their  feet  emitted  in  the  neighborhood  of  the 
post ;  and  that  they  could  tell  the  names  of  a  number  of  tame  pigeons,  with  which 
they  amused  themselves  in  a  little  garden,  by  only  hearing  them  fly  over  their 
heads." — Abercrombie,  ibid. 

When  we  add  to  these  facts  the  cases  of  hypereesthesia  so  common  in  somnam- 
bulism and  hypnotism,  we  see  that  it  is  impossible  to  put  a  limit  to  the  innate  or 
acquired  acuteness  of  our  senses.  As  to  this,  see  Braid,  "  Neurhypnology,"  p.  62. 
"  A  patient  who  could  not  hear  the  tick  of  a  watch  beyond  three  feet  when  avrake, 
could  do  so  when  hypnotized  at  the  distance  of  thirty-five  feet,  and  walk  to  it  in  a 
direct  line,  without  difficulty  or  hesitation  ....  Some  will  feel  a  breath  of  air 
from  the  lips,  or  the  blast  from  a  pair  of  bellows,  at  the  distance  of  fifty  or  even 
ninety  feet,  and  bend  from  it,  and,  by  making  a  back  current,  as  by  waving  the 
hand  or  a  fan,  will  move  in  the  opposite  direction." — These  experiments  have  been 
repeated  and  varied  by  Dr.  Azam  of  Bordeaux,  "  and  the  hearing,"  he  says,  "  at- 
tains such  acuteness  that  a  conversation  may  be  heard  on  the  floor  below.  The 
ticking  of  a  watch  is  heard  at  twenty  five  feet  distance."— So  with  the  smell,  taste,  sen- 
sations of  heat,  and  the  rest.  "  I  have  seen  a  person  write  correctly  with  a  book 
placed  between  him  and  the  paper ;  I  have  seen  a  fine  needle  threaded  in  the 
same  position  ;  have  seen  a  person  walk  about  a  room  with  his  eyes  entirely  closed 
and  bandaged,  and  all  this  without  any  other  real  guide  than  the  resistance  of  the 
air,  and  the  perfect  precision  of  the  movements  guided  by  the  muscular  sensations 
in  their hypersesthetic  state." — "  Annalcs  Medico-psychologiques,"  36  serie,  vi.  434. 


328  THE    KNOWLEDGE    OF  BODIES.  [BOOK  II. 

seem  to  us  at  once  distant  and  continuous  ;  then,  the  whole 
sensation,  composed  of  partial,  coexistent,  distinct,  and  con- 
tinuous sensations,  that  is  to  say  of  such  that  between  the 
position  of  one  and  that  of  another,  we  could  not  imagine  any 
intermediate,  will  appear  to  us  extended. — Let  the  reader  be 
good  enough  to  observe  his  own  case ;  he  will  see  that  this  is 
so  with  the  sensations  of  heat  and  cold,  which  seem  to  us  to 
occupy  a  whole  limb,  with  the  sensation  of  contact  and  pres- 
sure which  we  experience  in  laying  our  hand  flat  on  a  table, 
with  the  sensation  of  color  which  we  experience  when  we 
keep  the  eye  steadily  fixed  on  a  green  leaf  placed  at  six  feet 
distance.  In  all  these  cases,  the  sensation  seems  extended. 
This  arises  from  its  consisting  in  a  number  of  simultaneous 
sensations,  which  the  education  of  the  touch  causes  to  appear 
as  situated  in  distinct  and  continuous  points. — Here  there  is 
a  double  error,  first,  because,  as  we  have  seen,  sensations  are 
situated  in  the  sensory  centres,  and  not  in  the  nervous  per- 
ipheries, next,  because,  as  physiologists  show,  the  nervous 
axes  or  cylinders,  whose  disturbance  excites  our  sensations, 
form,  at  their  terminations,  discontinuous  lines  and  surfaces. 
The  extension  of  our  sensation  is  thus,  in  two  senses,  an  illu- 
sion. 

From  this  illusion  there  springs  another.  With  reference 
to  sensations  localized  in  points  of  our  body,  we  conceive  and 
affirm  the  existence  of  objects  situated  beyond  our  body,  that 
is  to  say  external,  and  we  determine  their  situation  by  the 
situation  of  the  sensation  which  reveals  them  to  us.  For  in- 
stance, a  sensation  of  smell  reaches  me,  and  I  at  once  con- 
ceive and  affirm  a  rose  to  be  situated  in  the  neighborhood  of 
my  nose.  I  experience  a  sensation  of  heat  which  I  refer  to 
my  left  leg ;  and  I  at  once  conceive  and  affirm  some  heated 
object,  a  current  of  hot  air,  a  stove,  a  fire-place,  as  situated 
near  my  left  leg. — The  more  determinate  and  precise  the 
locality  of  my  sensation,  the  more  precisely  do  I  determine 
the  locality  of  the  object.  This  is  what  happens  with  sen- 
sations of  contact,  and  especially  at  the  surface  of  the  skin, 
and  more  particularly  at  the  lips,  the  point  of  the  tongue,  the 
hand,  the  fingers,  the  tips  of  the  fingers  ;*  at  these  parts 

*  See  Weber's  Measurements,  Mueller,  "  Physiology  "  (tr.  Baly),  i.  701. 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES. 


329 


the  power  of  discrimination  is  very  delicate,  and  two  points 
separated  by  a  line,  or  even  half  a  line,  give  two  distinct 
sensations.  By  means  of  such  sensations,  we  are  able 
to  situate  an  object  very  exactly ;  their  position  is  very 
precise ;  consequently,  the  position  of  the  object  is  no 
less  precise. — This  position  is  still  more  precise  in  the  case 
of  sensations  of  color ;  consequently,  in  this  case,  the  posi- 
tion of  the  object  is  still  more  precise. — If,  now,  we  con- 
sider a  sharply  circumscribed  portion  of  these  very  sensi- 
tive surfaces,  and  admit  that,  when  all  the  nervous  points 
capable  of  affording  us  a  distinct  sensation  are  disturbed  at 
once,  we  may  have  a  sensation  apparently  extended  and  con- 
tinuous ;  we  shall  conceive  and  affirm  the  external  object  as 
extended  and  continuous.  This  is  at  present  our  usual  pro- 
ceeding. This  is  why,  by  means  of  a  total  sensation,  com- 
posed of  partial  and  simultaneous  sensations,  we  perceive  as 
extended  and  continuous  the  ground  on  which  our  foot  is 
resting,  the  portion  of  the  table  on  which  our  hand  is  ex- 
tended, the  distant  object  which  our  sensation  of  color  de- 
notes. We  start  from  the  extension  and  continuity  of  our 
sensation,  to  ascribe  to  the  object  a  similar  extension  and 
continuity ;  now,  the  continuity  and  extension  of  the  sensa- 
tion being  apparent  only,  that  of  the  object  can  only  be  ap- 
parent. Consequently,  the  extension  and  continuity  of 
bodies  are  illusions  only ;  and,  in  fact,  physicists  arrive  at 
conceiving  atoms,  if  they  exist,  as  separated  by  enormous 
intervals,  in  such  a  way  that  in  a  surface  which  appears  to  us 
continuous,  the  vacant  part  is  far  more  extensive  than  the 
occupied  part ;  going  deeper  still,  they  define  bodies  as  a 
system  of  mathematical  points,  with  relation  to  which  effects 
increase  or  decrease  according  to  distance. — At  all  events, 
there  is  nothing  to  prove  that  bodies  are  really  extended  and 
continuous ;  in  this  respect,  our  assertion  is  entirely  gratui- 
tous. Thus,  the  extension  which  we  ascribe  to  bodies  is,  in 
fact,  an  apparent  property  of  our  sensation,  a  property  which, 
by  a  natural  illusion,  we  transfer  to  bodies.  But  this  trans- 
fer is  not,  as  Kant  teaches,  the  effect  of  the  innate  and  inex- 
plicable structure  of  the  mind ;  it  is  the  effect  of  an  acquired 
disposition,  instituted  in  us  by  experience,  and  we  have  been 


330  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

able  successively  to  show  the  various  steps  of  this  acquisi- 
tion. 

Other  consequences  follow.  By  the  position  and  exten- 
sion we  attribute  to  our  sensations,  our  being  itself  seems  to 
us  situated,  extended,  circumscribed  in  a  precinct.  This  pre- 
cinct is  attached  to  the  personality,  and  henceforward,  the 
idea  I  have  of  myself  is  inseparable  from  the  idea  I  have  of 
my  body.  In  fact,  this  body  is  the  only  thing  that  accom- 
panies me  everywhere.  It  is  the  only  thing  which  answers 
to  my  touch  by  a  sensation  of  contact.  It  is  the  only  thing 
which  my  will  sets  directly  into  motion.  It  is  the  only  thing 
in  which  I  place  the  sensations  I  attribute  to  myself.  In  all 
these  respects  it  appears  to  me  so  tied  up  and  confounded  with 
myself,  that,  when  I  refer  a  sensation  to  any  point  whatever 
of  the  nervous  surface,  my  being  and  my  personality  seem  to 
me  for  the  moment  situated  at  the  spot  in  question.  Such 
is  the  present  state. — Hence  it  follows  that  when  I  now  touch 
a  table,  the  object  touched  must  appear  to  me  not  only  as 
other  than  myself,  but,  further,  as  without  me  and  without 
my  sentient  surface.  It  is  thus  opposed,  not  only  to  myself, 
but  also  to  the  enclosed  space  in  which  I  situate  my  person- 
ality, and  in  this  way,  for  the  first  time,  it  is  really  external. 

In  fact,  it  is  this  character  which  strikes  us  when  we  now 
perceive  a  body.  We  conceive  it  as  a  thing  beyond  us ;  to 
this  first  characteristic,  the  others  attach  themselves. — On 
moving  my  hand  about  in  the  dark,  it  meets  with  an  unknown 
obstacle  in  a  table ;  upon  this  sensation,  I  conceive  and  affirm 
beyond  my  hand  a  thing  beyond  it,  which  excites  in  me  a  con- 
tinuous and  extended  sensation  of  resistance,  and  which,  be- 
ing capable,  as  I  suppose,  of  exciting  it  again,  presently  and 
still  later  on,  in  others  as  well  as  in  myself,  thus  possesses 
the  permanent  and  general  property  of  being  resisting  and 
extended.  At  the  same  time,  the  shades  of  my  sensation 
and  the  accompanying  sensations  of  uniform  contact,  cold 
and  sound,  add  to  my  conception  the  idea  of  a  conical  form, 
of  a  metallic  and  sonorous  substance,  that  is,  of  a  bell. — Thus 
determined  and  qualified  by  the  group  of  sensations  it  ex- 
cites, this  thing  beyond  me  is  opposed  to  me  as  a  thing  without, 
to  a  thing  within. — The  separation  is  still  more  readily  effected 


CHAP.  II.]  THE  EDUCATION  OF  THE  SENSES.  33! 

when  the  perception  comes  through  the  eyes ;  and  ob/erve 
that,  at  present,  this  is  the  most  usual  process.  We  have 
shown  how,  in  sight,  the  sensation  of  the  retina  finds  itself 
projected  in  appearance  beyond  our  sentient  surface,  to  be- 
come incorporated  with  the  object  which  excites  it,  in  such  a 
way  that  color,  which  is  an  event  of  our  being,  seems  to  us 
a  quality  of  the  object.  When  I  perceive  this  silver  bell  at 
three  paces  from  me,  the  white  shining  patch  in  its  centre, 
which  appears  to  me  to  be  three  paces  off,  is  a  sensation  of 
the  retina  transported  from  its  seat  by  the  education  of  the 
eye.  In  this  case,  our  sensation  itself  appears  to  us  as  a  thing 
beyond  us  ;  consequently  the  object  to  which  we  attribute 
it,  and  which,  under  the  name  of  color,  it  seems  to  clothe,  is 
opposed  to  our  self  and  its  precinct  as  a  thing  external  and 
more  or  less  distant. — Sensations  apparently  projected  be- 
yond the  nervous  surface  in  which  we  situate  our  personality, 
lodged  in  a  determinate  point  of  this  outer  region,  detached 
from  us  by  this  projection,  constituted  apart  as  events  foreign 
to  us,  erected  into  permanent  qualities  by  the  continuity  and 
uniformity  of  their  repetition,  erected  into  qualities  of  a  solid 
body  by  the  presumed  possibility  of  a  sensation  of  contact 
and  resistance  at  the  spot  in  which  we  situate  them :  such 
are  the  visual,  and  really  internal,  phantoms  which,  when  we 
open  our  eyes,  seem  to  us  external  objects,  and  we  now  com- 
prehend without  difficulty  how  it  is  that,  being  compounds 
of  the  kind,  they  appear  to  us,  not  only  as  other  than  our- 
selves, but  as  situated  without  us. 

VIII.  Here  we  have  the  appearances,  and  it  is  time  to 
inquire  if  there  be  any  thing  real  corresponding  to  so  many 
illusions.  We  have  found  that  the  objects  we  call  bodies  are 
but  internal  phantoms,  that  is  to  say  fragments  of  the  Ego, 
detached  from  it  in  appearance  and  opposed  to  it,  though 
fundamentally  they  are  the  Ego  under  another  aspect ;  that, 
strictly  speaking,  this  sky,  these  stars,  these  trees,  all  this 
sensible  universe  which  each  of  us  perceives,  is  the  work  of 
each  of  us,  or  rather  his  emanation,  or  rather  his  creation,  an 
involuntary  creation,  effected  by  him  spontaneously  without 
his  consciousness  of  it,  and  extended  to  infinity  around  him 
like  the  shade  of  a  little  body  whose  outline  goes  on  increas- 


332  THE  KNOWLEDGE   OF  BODIES,  [BOOK  II. 

ing  in  proportion  as  it  becomes  distant,  and  ends  by  covering 
the  whole  horizon  with  its  immensity. — We  have  then  found 
that  no  one  of  our  sensations  is  situated  in  that  part  of  the 
body  in  which  we  place  it,  that  many  of  them,  though  belong- 
ing to  us,  appear  as  foreign  to  us,  that  among  these  some 
appear  as  permanent  qualities  of  a  being  other  than  ourselves, 
while  they  are  in  fact  transient  moments  of  our  being. — Thus, 
illusion  shows  itself  in  all  our  judgments,  whether  they  refer 
to  the  external  or  the  internal  world,  and  we  are  no  longer  as- 
tonished at  finding  the  Buddhist  Philosopher  reduce  the  Real  to 
momentary  events  of  his  Ego.  But  analysis,  after  destroy- 
ing, is  able  to  reconstruct,  and  in  observing  the  manner  in 
which  our  illusions  are  formed,  we  have  already  discovered 
how  they  lead  us  on  to  truths. 

Let  us  first  take  the  sensations  which  we  still  attribute 
to  ourselves,  but  which  we  project  from  their  cerebral  seat  to 
situate  them  in  the  organs,  and  in  general,  at  some  point  of 
our  nervous  periphery — namely,  those  of  taste,  smell,  con- 
tact, pressure,  muscular  contraction,  pain,  heat,  and  cold. 
No  doubt,  these  sensations  are  not  at  the  spot  in  which  they 
seem  to  us  situated  ;  but  there  is  usually  found  at  this  spot 
the  commencement  of  the  nervous  disturbance  which  excites 
them.  For,  as  a  general  rule,  each  variation  in  this  distur- 
bance and  in  its  real  position  is  represented  by  a  proportion- 
ate variation  in  the  sensation  and  its  apparent  position,  so 
that,  as  a  general  rule,  our  false  judgment  results  in  the 
same  conclusion  as  a  true  judgment.  It  serves  us  as  well ; 
it  suggests  to  us  the  same  provisions.  If  the  nervous  dis- 
turbance which  excites  the  sensation  of  pressure  increases 
in  strength,  the  sensation  of  pressure  increases  in  strength. 
If  the  nervous  disturbance  which  excites  pain  actually  changes 
place,  the  pain  seems  to  change  place.  The  differences  of  posi- 
tion which  our  ordinary  judgment  incorrectly  supposes  to  ex- 
ist between  two  sensations,  are  precisely  the  differences  of  posi- 
tion which  physiological  experiment  correctly  establishes  be- 
tween the  starting  points  of  the  two  corresponding  nervous  dis- 
turbances.— Thus  our  mind  hits  the  mark,  though  its  aim  is 
bad,  and  what  we  erroneously  allege  of  our  sensations  applies 
with  an  almost  absolute  and  almost  constant  exactitude  to 


CHAP.  II.]  THE  EDUCATION  OF   THE  SENSES.  333 

the  nervous  disturbance  connected  with  them.  Except  in 
those  rare  cases  in  which  the  nervous  trunks  and  centres 
enter  spontaneously  into  action,  this  application  is  always 
correct.  This  is  from  its  being  the  effect,  not  of  a  coinci- 
dence, but  of  a  harmony.  In  fact,  the  sensation  is  almost 
always  connected  with  the  disturbance  of  the  extremity  of 
the  nerve  ;  and  this  almost  constant  connection  was  necessary 
to  establish  in  me  the  constant  association  of  images  by 
which  I  now  situate  the  sensation  in  the  neighborhood  of  the 
nervous  extremity.  Consequently  if,  on  the  one  hand,  this 
connection  invariably  leads  me  astray  by  making  me  invariably 
situate  my  sensation  in  a  wrong  spot,  on  the  other  hand  it 
almost  invariably  retrieves  the  error,  by  almost  invariably 
determining  a  disturbance  of  the  nervous  extremity.  It  has 
two  consequences,  the  one  unfailing  and  indirect,  my  mental 
illusion,  the  other  direct  and  almost  unfailing,  the  disturbance 
of  the  extremity  of  the  nerve  ;  they  are  two  streams  starting 
from  the  same  source  ;  that  is  why  they  correspond.  If  to 
the  mental  illusion  there  almost  invariably  corresponds  the 
disturbance  of  the  nervous  extremity,  it  is  from  their  both 
arising  by  virtue  of  the  same  law. 

The  same  observation  applies  to  sensations  which  we 
project  beyond  our  sensible  precinct,  and  which  we  consider 
to  be  events  foreign  to  us,  as  for  instance  sounds,  or  qualities 
of  objects  foreign  to  us,  as  for  instance  colors. — No  doubt 
it  is  erroneously  that  a  particular  sound,  which  is  a  sensation 
of  my  acoustic  centres,  appears  to  me  to  float  in  the  air,  at 
twenty  paces  to  the  right ;  but  to  its  regular  or  irregular 
sound  corresponds,  element  for  element,  a  vibration  of  the 
air  which  is  propagated  from  this  point,  at  this  height,  this 
distance,  and  in  this  direction. — No  doubt,  again,  it  is  erro- 
neously that  the  white  and  blue  rays,  which  are  a  sensation 
of  my  optic  centres,  seem  to  me  extended  on  the  paper  with 
which  my  room  is  hung  ;  but  to  these  rays  of  color  corres- 
pond, element  for  element,  differences  of  structure  in  the 
surface  of  the  paper,  and  consequently  differences  of  aptitude 
to  absorb  or  reflect  the  different  luminous  rays.  Except  in 
the  rare  cases  in  which  the  ear  and  eye  have  subjective  sen- 
sations, the  correspondence  is  perfect.  So,  here  again,  our 


THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

judgment,  invariably  false  in  itself,  is  almost  invariably  true 
by  correspondence  and  coincidence.  What  we  erroneously 
affirm  of  our  sensations  is  found  true  of  something  else  ;  the 
variations  and  differences  of  the  object  coincide  with  the 
variations  and  differences  of  our  sensations. — The  fact  is,  that 
our  sensations  are  adjusted  to  things,  and  the  internal  order 
to  the  external.  Here,  as  before,  the  illusion  of  the  sense 
proceeds  from  its  education,  and  its  education  frdm  the  laws 
which  connect  the  origin  of  a  particular  sensation  to  the 
almost  constant  presence  of  a  particular  external  condition  ; 
so  that,  at  present,  when  the  illusion  is  produced,  the  external 
condition  is  almost  invariably  present.  The  law  which  has 
resulted  in  exciting  the  illusion  within  us  usually  occasions 
the  condition  without  us.  Admirable  mechanism,  which  de- 
ceives to  instruct  us,  and  leads  us  through  error  to  truth. 

The  disturbance  of  the  extremity  of  a  little  whitish  fibre, 
the  vibration  of  the  particles  of  a  gas,  the  special  structure  of 
an  illuminated  surface — these  are  the  real  equivalents  met 
with  under  the  illusion  which  displaces  and  disfigures  our 
sensations.  But  these  equivalents  themselves  are  bodies  con- 
sidered in  the  aspect  of  a  movement  they  undergo,  or  of  a 
quality  they  possess. — There  remains  then  for  us  to  distin- 
guish the  sense  and  value  of  a  deeper  illusion — that  which 
constitutes  external  perception,  and  by  which  we  affirm  the 
existence  of  bodies.  Is  there  anything  real  corresponding  to 
this  phantom  which  sensation  excites  in  us,  and  which  we 
term  a  body  ?  We  have  said  that  external  perception  is  an  ac- 
curate hallucination.  In  what  does  it  differ  from  hallucination 
strictly  so  called,  which  is  deceptive  ? — Analysis  has  already 
replied.  To  this  internal  and  transient  phantom  which  ap- 
peared as  a  permanent  and  independent  thing  there  usually 
corresponds,  characteristic  for  characteristic,  a  permanent  and 
independent  Possibility  and  Necessity,  the  possibility  of  cer- 
tain sensations  under  certain  conditions,  the  necessity  of  the 
same  sensations  under  the  same  conditions  with  the  addition 
of  a  complementary  one.  What  I  am  legitimately  and  truly 
entitled  to  assert  when  I  touch  this  ivory  ball,  is  a  group  of 
relations  between  certain  conditions  and  certain  sensations ; 
by  virtue  of  these  relations,  ever}'  sentient  being,  who  at 


CHAK  II.]  THE  EDUCATION  OF   THE   SENSES.  335 

any  moment  of  time  shall  place  himself  under  the  conditions 
in  which  I  am,  will  have  the  sensation  I  have,  and  the  other 
sensations  I  imagine.  The  law  is  a  general  one,  independent 
of  my  presence,  of  my  absence,  of  my  existence.  Its  perma- 
nence causes  me  to  imagine  a  metaphysical  entity — substance. 
Its  efficacy  causes  me  to  imagine  a  metaphysical  entity — force. 
These  are  convenient  symbols,  but  we  must  retain  them  in 
the  state  of  symbols.  Taken  in  this  sense,  we  may  say  that 
to  our  phantom  corresponds  a  substance,  independent  of  us, 
permanent,  possessed  of  effective  force,  capable  of  exciting 
in  every  sentient  being  a  certain  group  of  sensations,  more 
generally  still,  capable  of  exciting  and  undergoing  an  event 
which  we  have  recognized  as  the  equivalent  of  our  most 
important  sensations,  that  is  to  say  motion,  or  change  of 
place. 

But  while  availing  ourselves  of  these  phrases,  we  carefully 
preserve  the  recollection  of  their  inner  meaning.  We  remind 
ourselves  that  our  external  perception,  reduced  to  what  truth 
it  contains,  is  but  a  general  assertion,  the  enunciation  of  a  law, 
a  kind  of  prediction,  valid  for  the  past  as  for  the  future,  the 
prediction  of  certain  events,  sensations,  or  equivalents  of  sen- 
sations, as  possible  under  certain  conditions,  as  necessary 
under  the  same  conditions,  with  the  addition  of  a  complemen- 
tary one.  We  announce  that  every  sentient  being,  who  shall 
touch  or  shall  have  touched  the  ball,  will  have  or  will  have 
had  the  group  of  muscular,  tactile,  visual  sensations  which  we 
ourselves  had ;  that  'everybody  which  shall  come  or  shall  have 
come  into  collision  with  the  ball,  will  lose  or  will  have  lost  a 
portion  of  its  motion.  There  is  hallucination  proper,  when 
the  thing  announced  is  not  accomplished,  when  the  white 
spherical  form,  which  appears  situated  three  paces  from  me, 
does  not  excite  in  me  or  in  others  the  muscular  and  tactile 
sensations  on  which  I  reckoned,  when  a  body  which  passes 
through  the  spot  at  which  it  appears  to  me  situated,  does  not, 
in  spite  of  my  expectation,  undergo  any  diminution  of  its  mo- 
tion. But  this  case  is  very  rare,  and  the  agreement  between 
the  preliminary  announcement  and  the  subsequent  effect  is 
almost  constant.  This  means  that  there  is,  in  fact,  an  almost 
constant  connection  between  the  visual  sensation  of  this 


336  THE  KNOWLEDGE   OF  BODIES.  [BOOK  II. 

whitish  spherical  body  on  the  one  hand,  and  a  certain  group 
of  muscular  and  tactile  sensations  on  the  other ;  the  first  is 
the  indication  of  the  second ;  when  the  sensation  is  given, 
the  group  is  almost  invariably  possible ;  when  the  first  is 
given,  in  almost  every  case,  if  there  be  added  the  comple- 
mentary condition — the  transport  of  the  hand  to  the  proper 
place — the  second  becomes  necessary.  Now  my  constant 
prediction  is  in  my  case  the  fruit  of  this  almost  constant  con- 
nection. Consequently,  the  infallible  springing  up  of  the  pre- 
diction supposes  the  almost  infallible  presence  of  the  group, 
and  the  course  of  events,  which,  by  its  regularity,  has  created 
my  attempt,  finds,  in  this  very  regularity,  cause  to  justify -it. 
All  this  mechanism  is  admirable,  and  the  reader  now  sees 
the  length  of  the  elaboration,  the  perfection  of  the  adjust- 
ment, which  permit  us  to  form,  effectually  and  successfully, 
an  act  so  usual,  so  short,  so  easy,  as  external  perception. 
The  operation  resembles  digestion  or  walking;  apparently, 
there  is  nothing  more  simple  ;  in  reality,  there  is  nothing  more 
complex. — There  is,  in  front  of  me,  three  paces  off,  a  book 
bound  in  brown  leather,  and  my  eyes  are  open.  A  certain 
sensation  of  brown  color  rises  in  my  optic  centres ;  in  other, 
centres  rise  muscular  sensations  excited  by  the  adjustment 
of  my  eye  to  the  distance,  by  the  convergence  of  the  two  eyes, 
by  the  direction  of  the  convergent  eyes  ;  these  sensations  vary 
with  the  sensation  of  brown  color,  in  proportion  as  the  eye, 
in  its  movements,  follows  the  outline  and  variously  illumin- 
ated portions  of  the  book.  There  are  two  series  of  sensations, 
whose  position  is  in  the  box  of  the  skull :  these  are  the  crude 
materials. — All  the  ulterior  process  consists  in  a  coupling  of 
images.  Thanks  to  the  associated  image  of  the  muscular  sen- 

o  o 

sations  which  would  conduct  the  exploration  of  touch  up  to 
and  along  the  book,  the  sensation  of  color,  which  belongs  to 
us,  ceases  apparently  to  belong  to  us,  and  appears  an  extend- 
ed patch  situated  three  paces  from  our  eyes. — Thanks  to  the 
associated  image  of  the  sensations  of  contact  and  resistance 
which  our  exploring  touch  would  then  experience,  the  patch 
seems  to  us  a  solid  extension. — Thanks  to  the  associated  im- 
age of  the  sensations  which  would  be  experienced  at  any  time 
by  any  being  similar  to  ourselves,  it  seems  to  us  that  there 


CHAP.  II.]  THE  EDUCATION  OF   THE   SENSES. 

is  at  that  spot,  something  permanent,  independent,  and  capa- 
ble of  exciting  sensations,  and  which  we  term  matter. — Thus 
arises  the  internal  semblance,  composed  of  an  alienated  and 
wrongly  situated  sensation,  of  associated  images,  and,  more- 
over, in  the  man  who  reflects,  of  an  interpretation  and  a  name 
which  isolate  and  set  apart  a  permanent  character  included  in 
the  group. — This  semblance  changes  at  every  moment  with 
the  sensations  which  form  its  support.  On  each  new  support 
the  associated  images  construct  a  new  semblance,  and  the 
mind  is  filled  with  innumerable  inmates,  a  transient  popula- 
tion to  which  corresponds,  each  to  each,  the  fixed  population 
of  the  outer  world. 

22 


THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 


BOOK  III. 

THE  KNOWLEDGE  OF  MIND. 


CHAPTER  I. 

THE  KNOWLEDGE   OF    MIND. 

I.  HERE,  then,  we  have  reached  the  unextended  centre, 
a  species  of  mathematical  point,  by  relation  to  which  we  de- 
fine all  the  rest,  and  which  each  of  us  calls  /  or  me.  We  re- 
vert to  it  at  every  instant  of  our  life ;  a  very  intense  contem- 
plation, almost  amounting  to  ecstasy,  is  requisite  to  detach 
us  wholly  from  it,  and  to  cause  us  to  forget  it  for  some  min- 
utes ;  even  then,  by  a  sort  of  rebound,  we  re-enter  upon  our- 
selves with  greater  energy ;  we  mentally  review  all  the  fore- 
going scene,  and  say,  mentally,  twenty  times  in  a  minute; 
"  Just  now  I  was  in  such  a  place,  I  looked  in  such  a  direction, 
then  in  another,  I  had  such  an  emotion,  I  made  such  a  gest- 
ure, and  now  I  am  here." — Besides  this,  the  idea  of  ourselves 
is  comprised  in  all  our  recollections,  in  almost  all  our  previ- 
sions, in  all  our  pure  conceptions  or  imaginations. — Moreover 
it  is  called  up  by  all  our  sensations  in  any  way  strange  or  vivid, 
especially  those  of  pleasure  or  pain,  and  we  often  forget  the 
external  world  almost  completely  and  for  a  considerable  length 
of  time,  to  recall  some  agreeable  or  interesting  passage  of  our 
life,  to  imagine  or  desire  some  great  good  fortune,  to  observe 
in  the  distance,  either  past  or  future,  some  series  of  our  emo- 
tions.— But  this  ourselves,  to  which,  by  a  perpetual  recurrence, 
we  attach  each  of  our  successive  events,  is  far  more  extensive 
than  any  one  of  them.  It  is  drawn  out  before  our  eyes  with 
certainty,  like  a  continuous  thread,  backwards,  over  twenty, 
thirty,  forty  years,  up  to  the  most  distant  of  our  recollections, 
and  further  still,  up  to  the  beginning  of  our  life,  and  it  is 
drawn  out  too,  by  conjecture,  forwards,  into  other  indetermi- 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  339 

nate  and  obscure  distances.  For  each  new  link  we  add  to  it 
we  review  a  longer  or  shorter  fragment,  a  minute,  an  hour,  a 
day,  a  whole  year,  many  years,  sometimes  an  enormous  por- 
tion in  the  twinkling  of  an  eye,  and  as  if  in  a  flash  of  light- 
ning. This  is  why,  when  compared  to  our  transient  events, 
this  Ego  assumes  a  sovereign  importance  in  our  eyes. — We 
must  now  examine  what  idea  we  have  of  it,  of  what  elements 
this  idea  is  composed,  how  it  is  formed  within  us,  why  it  is 
called  up  by  each  of  our  events,  what  thing  corresponds  to  it, 
and  by  what  adjustment  this  correspondence  of  the  thing  and 
idea  is  effected. 

II.  What  do  we  understand  by  an  Ego,  in  other  words  by 
a  person,  a  soul,  a  spirit  ?  When  we  conceive  some  living 
man,  Peter,  Paul,  or  ourselves,  what  idea  is  there  within  us, 
and  of  what  elements  is  this  idea  composed  ? — What  we  af 
firm  is,  in  the  first  place,  a  something,  a  being ;  I  purposely 
employ  the  vaguest  language,  so  as  not  to  prejudice  the  mat- 
ter. But,  in  pronouncing  these  words,  we  affirm  nothing  of 
this  thing,  except  that  it  is  ;  we  say  nothing  of  what  it  is, 
that  question  we  reserve. — What  we  affirm  is,  secondly,  that 
it  is  a  permanent  being  ;  there  is  something  in  it  which  lasts 
and  remains  the  same.  I  exist  to-day,  but  I  existed  yesterday 
and  the  day  before;  and  so  with  Peter  and  Paul.  If  both 
they  and  I  have  changed  in  some  respects,  in  other  respects 
they  and  I  have  not  changed,  and  I  conceive,  in  them  as  in 
myself,  something  which  has  remained  fixed.  But,  in  saying 
this,  I  do  but  affirm  the  permanence  of  something  in  them 
and  me ;  I  do  not  say  what  this  something  is  ;  I  state  its  dura- 
bility, not  its  quality  ;  that  question  we  also  reserve. — What 
we  affirm  is,  thirdly,  that  this  something  is  connected  with  a 
particular  organized  body  ;  I  have  mine,  Peter  and  Paul  have 
each  their  own,  and  we  mean  thereby  to  say  that,  as  a  general 
rule,  certain  alterations  of  my  body  excite  in  me  directly 
some  particular  sensations,  and  that  certain  events  in  me — 
emotions  or  volitions — excite  directly  in  my  body  certain  al- 
terations ;  the  same  being  the  case  with  Peter,  Paul,  and  their 
respective  bodies.  But  this  rule  only  states  a  constant  rela- 
tion between  certain  changes  of  a  particular  body  and  cer- 
tain states  of  the  unknown  something  ;  what  that  relation  is, 


340  THE  KNOWLEDGE    OF  MIND.  [Boou  III. 

still  remains  to  be  examined ;  that  question  we  again  reserve. 
— After  having  stated  its  existence,  its  permanence,  and  its 
principal  relation,  we  must  now  inquire  into  the  qualities 
which  determine  it. 

These  qualities  are  its  capacities  and  faculties.  I  am  capa- 
ble of  feeling,  of  perceiving  external  objects,  of  recollecting, 
of  imagining,  of  desiring,  of  willing,  of  contracting  my  mus- 
cles, and  in  this  respect,  Peter,  Paul,  and  other  men  are  similar 
to  myself.  Moreover,  in  addition  to  these  capacities  common 
to  all  men,  I  have  others  special  to  myself ;  for  instance,  I  am 
able  to  understand  a  Latin  book ;  this  porter  can  carry  a 
weight  of  300  pounds ;  here  are  precise  capacities  which  de- 
termine the  unknown  something.  Let  us  reunite  in  one 
group  and  one  bundle  all  these  capacities  and  faculties,  com- 
mon or  special,  which  are  met  with  in  any  one,  and  we  shall 
know  what  he  is,  in  knowing  what  he  contains.  The  vague 
and  empty  sketch,  which  we  had  of  the  Ego  or  of  the  person, 
becomes  limited  and  is  filled  out. 

III.  Here,  then,  we  are  led  to  inquire  into  what  we  mean 
by  capacities  and  faculties.  I  have  the  capacity  or  faculty  of 
feeling ;  this  means  that  I  am  capable  of  having  sensations; 
sensations  of  various  kinds,  of  smell,  taste,  cold,  heat,  and, 
for  instance,  of  sound.  In  other  words,  sensations  of  sound 
which,  if  they  arise,  will  be  mine,  are  possible.  They  are  pos- 
sible because  their  condition  is  given,  that  is,  a  certain  state 
of  my  acoustic  apparatus  and  of  my  sensory  centres ;  if  this 
condition  ceased  to  be  given,  they  would  cease  to  be  possible  ; 
I  should  no  longer  be  able  to  hear  sounds  ;  I  should  be  deaf. 
— And  so,  a  man  has  the  faculty  or  power  of  perceiving  exter- 
nal bodies,  especially  by  sight ;  this  means  that  sensations  of 
sight,  which,  if  they  arise,  will  be  his,  are  possible.  They  are 
possible  upon  two  conditions  ;  his  optical  and  cerebral  appar- 
atus must  be  in  the  proper  state,  and  the  education  of  the 
sight  must  have  associated  in  him  with  optical  sensations  the 
image  of  certain  muscular  sensations  ;  as  these  two  conditions 
are  given,  his  perceptions  are  possible ;  if  one  or  the  other 
were  suppressed,  his  perceptions  would  cease  to  be  possible  ; 
he  would  lose  or  would  incompletely  possess  the  faculty  of 
sight. — So  it  is  in  all  other  cases,  whether  we  consider  a  facul- 


CHAP.  I.]  THE  KNOWLEDGE    OF  MIND.  341 

ty  common  to  all  men  or  a  faculty  special  to  an  individual.  I 
have  the  power  or  faculty  of  moving  my  limbs,  and  of  retain- 
ing my  ideas  persistently.  This  means  that  this  movement 
of  my  limbs  and  this  persistence  of  my  ideas  is  possible ;  the 
movement  is  possible  because  its  condition — a  certain  state 
of  my  muscular  and  nervous  system — is  given ;  this  persist- 
ence is  possible  because  its  condition — a  certain  equilibrium 
of  my  images — is  given. — I  have  the  faculty  of  understanding 
a  Latin  book,  and  my  neighbor  the  porter  has  the  faculty  of 
carrying  a  load  weighing  300  pounds ;  this  means  that  if  I 
read  a  Latin  book,  I  shall  understand  it ;  that  if  the  porter 
has  a  load  of  300  pounds  weight  on  his  back,  he  will  carry  it. 
The  first  act  is  possible  to  me,  because  its  condition — the 
knowledge  of  the  Latin  words — is  given  ;  the  second  is  possi- 
ble to  the  porter,  because  its  conditions— the  development  of 
his  muscles  and  the  habitude  of  bodily  exercise — are  given. 
Suppress  one  of  these  conditions  ;  the  possibility  disappears, 
and  the  faculty  perishes,  until  the  missing  condition  is  re-es- 
tablished. Soften  and  waste  away  the  porter's  muscles  by  a 
month's  low  diet ;  he  will  no  longer  be  able  to  lift  his  load. 
If  paralysis  benumbs  the  nerves  of  my  arm,  I  shall  no  longer 
be  able  to  lift  that  arm.  If  an  hallucination  prevents  my  sen- 
sory centres  from  receiving  the  impression  produced  on  my 
retina  by  the  rays  emanating  from  the  table ;  as  long  as  the 
hallucination  lasts,  I  shall  be  unable  to  perceive  the  table  by 
sight. — On  the  other  hand,  cure  the  hallucination  and  the  par- 
alysis, and  strengthen  the  weakened  muscles  ;  the  possibili- 
ties, and  with  them  the  suspended  faculties,  will  re-arise  as 
they  were  before. 

Thus,  faculty  and  capacity  are  wholly  relative  terms  ;  and 
here  we  fall  again  into  a  similar  analysis  to  that  which  we 
effected  with  the  properties  .of  bodies.  All  these  words  are 
equivalent  to  that  of  power ;  and,  whatever  be  the  power, 
that  of  a  dog  which  can  run,  that  of  a  mathematician  who  can 
solve  an  equation,  that  of  an  absolute  king  who  can  cause 
heads  to  be  cut  off,  the  word  never  does  more  than  state  that 
the  conditions  of  an  event  or  of  a  class  of  events  are  present. 
— There  is  nothing  more  useful  than  the  knowledge  of  such 
conditions  ;  it  permits  us  to  foresee  events,  those  of  others  as 


342  THE      KNOWLEDGE  OF  MIND.  [BOOK  III. 

well  as  our  own.    Consequently,  we  attach  a  great  importance 
to  these  powers ;  they  are  to  us  the  principal  and  essential 
part  of  things ;  we  are  tempted  to  form  of  them  distinct  en- 
tities, to  consider  them   as  a  primitive  foundation,  a  stable 
groundwork,  an   independent   and   productive   source   from 
which  events  flow. — The  truth,  however,  is  that  a  power  is 
nothing  in  itself,  except  an  aspect,  an  extract,  a  particularity 
of  certain  events,  the  particularity  they  have  of  being  possi- 
ble because  their  conditions  are  given.     If  these  events  are 
mine  or  a  consequence  of  mine,  the  power  appertains  to  me. 
In  saying  that  I  have  such  a  power,  I  do  but  announce  as 
possible  such  an  event,  sensation,  perception,  emotion,  voli- 
tion, which  will,  perhaps,  form  part  of  my  being,  and  some 
other  event,  muscular  contraction,  carriage  of  a  load,  execu- 
tion of  an  order,  which  will  follow,  sooner  or  later,  a  possible 
state  of  my  being.     But  these  events  and  states  are  supposed, 
not  given  ;  they  do  but  form  part  of  my  possible  being,  they 
do  not  form  part  of  my  real  being.     One  only  of  them  will 
arise   at   any   particular   moment ;  the   others,  in   unlimited 
number,  will  not  arise.     The  others  will  remain  on  the  thresh- 
old, or  outside ;  this  single  privileged  one  will  enter   alone> 
and  will  alone  form  part  of  myself.      I  find,  then,  by  way  of 
real  elements  and  positive  materials,  to  constitute  my  being, 
nothing  but  my  events  and  states,  future,  present,  and  past. 
What  there  is  actually  in   me  is  their  series   or  web.     I  am, 
then,  a  series  of  successive  events  and   states,  sensations,  im- 
ages, ideas,  perceptions,  recollections,  previsions,  emotions, 
desires,   volitions,  connected   together,    excited    by    certain 
changes  of  my  body  and  of  other  bodies,  and  exciting  certain 
changes  of  my  body  and  of  other  bodies.     And,  as  it  is  plain 
that  my  events,  past,  future,  or  possible,  are  all  more  or  less 
analogous  to  the  daily  events  which  I  can  seize  at  the  mo- 
ment, or  almost  at  the  moment,  at  which  they  are  produced, 
these  last,  the  clearest  and  most  near  to  us  of  all,  are  what  I 
proceed  to  study  to  know  what  constitutes  the  Ego. 

IV.  Let  us,  then,  consider  one  of  these  events,  or  groups 
of  present  events,  some  sensation  of  pain  or  pleasure,  of  con- 
tact, of  temperature,  of  taste  or  smell,  some  tactile  and  mus- 
cular sensation,  some  preponderant  image,  some  preponder- 


CHAP.  I.]  THE  EDUCATION  OF   THE  SENSES.  243 

ant  mental  word,  some  emotion,  desire,  or  volition. — At  the 
present  moment  I  suffer  from  headache,  or  I  taste  a  fine 
fruit,  or  enjoy  myself  by  warming  my  limbs  in  the  chimney- 
corner  ;  I  imagine  or  recollect,  I  am  vexed  or  enlivened  by 
an  idea,  I  decide  on  taking  some  step.  These  are  the  events 
I  find  within  me  ;  active  or  passive,  voluntary  or  involuntary, 
whatever  be  their  shades,  it  is  of  no  importance  ;  they  con- 
stitute my  present  being,  and  I  attribute  them  to  myself. 
Now,  all  the  events  I  attribute  to  myself  have  a  common 
character ;  they  appear  to  me  as  internal. 

Let  us  begin  with  the  most  frequent  of  all,  that  is  to  say 
the  representations,  ideas,  and  conceptions  which  we  have  of 
objects,  and  especially  of  external  bodies  :  for  instance,  I  repre- 
sent to  my  myself  an  old  time-piece  in  the  adjoining  room. 
Furniture,  interiors  of  rooms,  human  or  animal  figures,  trees, 
houses,  streets,  landscapes — it  is  representations  of  this  class 
whose  series  composes  the  ordinary  current  of  our  thought. 
By  a  mechanism  we  have  described,  their  hallucinatory  ten- 
dency is  checked  :  they  are  affected  by  a  contradiction  which 
negatives  them  as  external  objects ;  they  are  thus  opposed 
to  external  objects  ;  in  other  words,  they  appear  internal. — 
So  it  is  with  every  idea,  sensible  or  abstract,  simple  or  com- 
pound. For  an  idea  is  always  the  idea  of  some  thing,  and 
consequently  comprises  two  phases,  the  first  an  illusory  one, 
in  which  it  seems  the  thing  itself;  the  second  a  rectified  one, 
in  which  it  appears  a  simple  idea.  This  transformation  it  un- 
dergoes opposes  to  each  other  the  two  phases  which  consti- 
tute it ;  we  express  this  passage  by  saying  that  we  re-enter 
upon  ourselves,  and  that,  from  the  object,  we  revert  to  the 
subject ;  it  is,  then,  the  same  event  or  group  of  events  which, 
according  to  its  successive  states,  constitutes,  first,  the  ap- 
parent object,  then  the  actual  subject. — Thus  the  rectifying 
operation,  by  which  an  idea  appears  as  an  idea,  is  also  the  re- 
flection by  which  this  idea  appears  as  something  internal ; 
and  the  contradiction  which  negatives  it  as  a  fragment  of  the 
outer  world  gives  it  at  the  same  time  a  position  as  a  frag- 
ment of  the  inner  world. 

We  must  now  observe  that  every  idea,  conception,  and 
representation  has  a  double  face.  On  the  one  hand,  it  is  a 


344  THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 

cognition  ;  on  the  other  hand,  it  is  an  emotion.  It  is  agreea- 
ble, painful,  surprising,  startling,  tender,  consoling.  Its  en- 
ergy, its  weakenings,  its  intermittences,  are  precisely  the  en- 
ergy, the  weakening,  the  intermittences  of  the  emotion. 
There  is  but  one  and  the  same  fact  with  two  aspects,  one  in- 
tellectual, the  other  affective  and  impulsive. — You  are  told 
that  some  one  whom  you  left  yesterday  in  good  health  has 
suddenly  died,  and  this  idea  upsets  you.  You  are  told  that 
a  near  relation  is  seriously  ill,  and  this  idea  afflicts  you.  It 
excites  a  general  shock,  or  kind  of  sharp  pain,  which  contin- 
ues, though  growing  feebler,  and  thus  causes  a  lasting  disor- 
der. There  is  nothing  strange  in  this  long  trouble,  which 
starts  from  an  idea  and  lasts  over  a  series  of  ideas,  seeming 
to  us,  like  the  ideas,  internal;  in  the  desires  and  volitions 
which  spring  from  it  being  similarly  referred  to  within  ;  in  the 
sequences  and  characters  of  the  ideas  being  opposed,  like  the 
ideas,  to  the  outer  world,  and  incapable  of  finding  a  place 
there. 

There  remains  for  inquiry,  why  the  sensations  which  we 
localize  in  our  bodies  also  appear  to  us  as  internal,  and  are 
referred  by  us  to  ourselves. — To  find  the  reason  of  this,  it  is 
sufficient  to  compare  them  with  those  equally  belonging  to 
us,  and  which  nevertheless  we  do  not  attribute  to  ourselves, 
those  of  color  and  sound.  We  have  seen  the  mechanism 
which  projects  these  in  appearance  beyond  our  body ;  if  they 
are  alienated  from  us,  it  is  because  they  are  projected  out  of 
our  precinct.  It  is,  then,  because  the  others,  those  of  con- 
tact, of  pressure,  of  heat,  of  muscular  effort,  of  local  pain,  of 
taste,  and  smell,  are  not  projected  beyond  our  body,  that  they 
are  not  alienated  from  us ;  their  position  is  the  cause  of  their 
attribution  ;  we  refer  them  to  ourselves  because  our  body, 
compared  with  others,  has  singular  and  special  characters. — 
In  fact,  it  is  by  its  medium  that  we  perceive  other  bodies  and 
act  upon  them.  Whether  the  action  comes  from  us  or  them, 
it  is  always  between  them  and  us.  In  order  for  us  to  know 
other  bodies,  it  is  first  necessary  for  one  of  the  organs  of  cm- 
body  to  be  disturbed ;  in  order  for  us  to  impress  motion  on 
other  bodies,  it  is  first  necessary  for  one  of  the  muscles  of  our 
body  to  be  contracted.  It  is  our  first  movable  thing,  and 


CHAP.  I.]  THE  KNOWLEDGE   OF    THE    SENSES  345 

first  motive  power ;  with  relation  to  other  things,  it  is  always 
inside ;  with  relation  to  it,  other  things  are  always  outside. 
It  is  our  immediate  precinct,  in  such  a  way  that,  if  we  com- 
pare it  to  other  things,  it  is  a  within  and  they  are  a  without* 
—This  is  why  the  sensations  of  which  we  have  been  speaking, 
though  placed  by  us  in  our  organs,  appear  as  internal,  and 
are  referred  to  self. — Such  is  our  conception  of  the  actual 
subject ;  these  are  the  present  and  real  facts  it  comprises. 
That  which  I  actually  am,  that  which  constitutes  my  real  be- 
ing, is  a  certain  present  real  group  of  sensations,  ideas,  emo- 
tions, desires,  volitions ;  my  conception  of  my  actual  being 
comprises  these  events  only,  and  all  these  events,  on  analysis, 
present  this  common  character,  that  they  are  pronounced  in- 
ternal, whether  because,  as  ideas  and  sequences  of  ideas,  they 
are  opposed  to  objects  and  deprived  of  situation,  or  because 
their  apparent  position  is  met  with  in  our  body. 

V.  Now,  at  the  preceding  moment,  the  subject  being 
wholly  similar,  contained  events  only  of  the  same  class ;  the 
same  observation  is  to  be  made  for  each  of  the  anterior  mo- 
ments. And,  in  fact,  when  we  consider  any  of  these  moments 
by  recollection,  we  find  they  are  all  similar  to  the  present  mo- 
ment ;  just  now,  when  in  the  other  room,  I  felt  cold,  and 
walked,  I  looked  at  the  clock,  I  foresaw,  I  desired,  I  willed,  as 
at  this  moment.  Consequently,  my  past,  as  my  present  events, 
have  all  this  character  of  appearing  internal. — In  this  way 
they  form  a  chain,  whose  links,  all  composed  of  the  same 
metal,  appear  at  once  united  and  distinct.  For,  according  to 
the  mechanism  we  have  described  and  explained,  on  the  one 
hand  the  image  which  constitutes  a  recollection  seems  pro- 
jected backwards,  and  recedes  beyond  the  repressive  images 
or  sensations,  which  separates  it  from  them ;  and,  on  the 
other  hand,  the  same  image,  becoming  precisely  situated, 
seems  to  be  joined  by  its  posterior  extremity  to  the  anterior 
extremity  of  the  repressive  images  or  sensations,  and  is  thus 
joined  to  them  ;  so  that  our  events  appear  to  us  as  a  continuous 
line  of  contiguous  elements.  We  pass  without  difficulty  from 
one  link  to  another  ;  according  to  the  well-known  law  which 
governs  the  revival  of  images,  the  images  of  two  successive 
sensations  mutually  tend  to  call  each  other  up  ;  when,  there- 


346  THE  KNOWLEDGE  OF  MIND.  [BOOK  III. 

fore,  the  image  of  some  one  of  our  anterior  moments  revives 
in  us,  the  image  of  the  preceding  and  that  of  the  succeeding 
moment  tend  to  revive  by  association  and  correspondence. 

Not  only  do  we  pass  by  these  means  from  one  of  our  mo- 
ments to  an  adjacent  one  ;  but,  by  means  of  abbreviations 
which  collect  in  one  image  a  long  series  of  moments,  we  pass 
from  one  period  to  another  of  our  life.  In  fact,  if,  in  order  to 
recollect  one  of  our  somewhat  distant  events,  it  were  neces- 
sary to  call  up  the  images  of  all  our  intermediate  sensations, 
the  operation  would  be  of  prodigious  length  ;  strictly  speak- 
ing, it  would  require  as  much  time  as  elapsed  between  that 
event  and  the  present  moment.  For  the  whole  detail  and  du- 
ration of  the  intermediate  sensations  are  reproduced  in  the 
images  which  conduct  us  backwards  to  that  event ;  it  would 
thus  require  twenty-four  hours  to  recall  a  sensation  of  yester- 
day. For  this  Nature  has  supplied  a  remedy  in  the  oblitera- 
tion which  images  undergo,*  and  in  the  property  possessed 
by  certain  prominent  images  of  being  the  abbreviatory  sub- 
stitutes of  the  group  in  which  they  are  included. — For  in- 
stance, this  morning  I  went  into  such  a  street,  and  such  a 
house  ;  at  present,  if  I  recall  my  walk,  numbers  of  details  are 
missing  ;  many  of  my  sensations  do  not  revive.  I  do  not  see 
again  the  different  figures  of  the  houses,  carriages,  and  pass- 
ers-by, which  I  then  saw  ;  nine  out  of  ten  of  them  are  oblit- 
erated definitively  and  for  ever ;  of  all  these  impressions  there 
is  but  a  remnant  capable  of  reviving.  Again,  it  almost  always 
happens  that,  in  ordinary  life,  I  do  not  give  it  time  to  rise ;  it 
would  be  necessary  for  me  to  dwell  on  it,  to  search  in  my 
memory.  It  is  only  when  I  search  that  I  see  again  certain 
precise  details,  some  shop,  some  interesting  countenance, 
some  striking  part  of  the  street.  If  I  do  not  dwell  on  it,  if  I 
do  not  drive  away  supervening  impressions  and  distractions, 
if  I  do  not  give  my  recollections  time  to  become  precise  and 
complete,  they  almost  all  remain  in  the  latent  state  ;  that 
which  survives  and  emerges  is  one  fragment  out  of  ten 
thousand,  the  vague  representation  of  my  progress  at  some 
moment  in  the  street,  of  my  arrival  in  the  house,  or  of  the  at- 


*  Part  i.  book  ii,  chapter  ii. 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  347 

titude  of  the  friend  I  went  to  see. — But  this  is  enough  ;  the 
shred  which  is  preserved  supplies  the  place  of  the  rest ;  I 
know  by  experience  that  by  concentrating  my  attention  upon 
it,  I  should  revive  several  similar  ones  of  the  same  series ;  it 
is  to  me  in  future  the  summary  representation  of  the  whole. 
— So  is  it  with  the  breakfast  I  had  previously  eaten,  with  the 
reading  which  occupied  the  first  hours  of  the  morning ;  so 
that,  with  three  abbreviatory  substitutes,  I  remount  in  a  mo- 
ment to  my  getting  up,  that  is  to  say  to  an  incident  separated 
by  ten  hours  from  the  present  moment. 

The  more  distant  the  event,  the  greater  is  the  obliteration 
of  the  images ;  and  the  greater  the  obliteration,  the  more 
things  does  the  abbreviatory  substitute  comprise. — My  doings 
of  yesterday  or  the  previous  day  subsist  in  me  only  through 
some  striking  event,  some  visit  I  received,  some  domestic  oc- 
currence for  which  it  was  necessary  to  provide.  If  I  recede 
still  further,  I  perceive  only,  in  the  shipwreck  an  irremediable 
swallowing  up  of  my  innumerable  anterior  sensations,  a  few 
surviving  images,  my  arrival  at  the  country  house  I  am  stay- 
ing in,  the  first  green  leaves  of  spring,  a  winter's  evening  at  a 
particular  house,  the  appearance  of  a  strange  town  I  visited  a 
year  ago.  I  may  thus  go  back  very  far  and  very  fast,  and  by 
springing  from  peak  to  peak,  may  reach  in  an  instant  things 
ten  or  twenty  years  distant. — Add  to  this  the  calendar,  cal- 
culations, all  the  different  means  which  we  possess,  and  which 
children  and  savages  do  not  possess,  of  measuring  this  distance. 
Thanks  to  an  association  of  images,  we  place  our  events  in  the 
series  of  days  and  months  with  which  the  almanac  furnishes 
us,  in  the  series  of  years  furnished  by  chronology.  When 
this  is  effected,  we  render  precise,  by  these  auxiliary  charts, 
the  position  which  our  various  events  occupy  in  duration  with 
reference  to  one  another,  and  are  able,  not  only  to  review  in 
a  second  our  most  distant  events,  but  also  to  estimate  the  in- 
terval separating  them  from  the  present. 

By  this  operation,  more  or  less  perfected,  we  embrace  very 
long  fragments  of  our  being  in  an  instant,  and,  so  to  speak, 
in  a  single  glance.  The  distinct  events  whose  succession  has, 
during  this  interval,  constituted  our  being,  cease  to  be  dis- 
tinct ;  they  are  obliterated  by  the  abbreviations  and  the 


348  THE  KNOWLEDGE  OF  MIND.  [BOOK  III. 

speed  ;  nothing  of  the  series  survives,  except  a  character  com- 
mon to  all  the  elements  traversed,  the  particularity  they  have 
of  being  internal.  There  remains,  then,  the  idea  of  an  internal 
something,  of  a  ^vithin,  which  is,  in  this  respect,  opposed  to 
all  the  without,  which  is  always  met  with  the  same  at  all  mo- 
ments of  the  series,  which,  consequently,  lasts  and  subsists, 
which,  for  this  reason,  appears  to  us  of  superior  importance, 
and  which  attaches  to  itself,  as  accessories,  the  various  tran- 
sient events.  This  stable  within  is  what  each  of  us  calls  /  or 
me.* — Compared  to  its  events,  which  pass  away  while  it  sub- 
sists, it  is  a  substance  ;  it  is  denoted  by  a  substantive  or  a  pro- 
noun, and  it  incessantly  reverts  to  the  most  prominent  place 
in  oral  or  mental  discourse. — Henceforward,  when  we  reflect 
on  it,  we  permit  ourselves  to  be  duped  by  language  ;  we  for- 
get that  its  permanence  is  apparent,  that,  if  it  appears  fixed, 
it  is  because  it  is  incessantly  repeated,  that  it  is  in  itself  noth- 
ing more  than  an  extract  from  internal  events,  that  it  derives 
from  them  all  its  being,  that  this  borrowed  being,  detached 
by  fiction,  isolated  by  the  oblivion  of  its  connections,  is  noth- 
ing in  itself  and  apart.  If  we  do  not  undeceive  ourselves  by 
a  rigid  analysis,  we  fall  into  metaphysical  illusion  ;  we  are  dis- 
posed to  conceive  it  as  a  distinct  thing,  stable  and  independent 
of  its  modes  of  being,  and  even  capable  of  subsisting  after  the 
series  from  which  it  is  derived  has  disappeared. 

Another  metaphysical  illusion  comes  in  to  complete  its 
being  and  effect  its  isolation.  We  have  classed  its  events 
and  the  facts  which  its  events  excite  according  to  their  re- 
semblances and  differences,  and  we  have  placed  each  group 
in  a  distinct  compartment  and  under  a  common  name — here 
sensations,  there  external  perceptions,  there,  again,  recol- 
lections, volitions,  voluntary  movements,  and  so  on.  Con- 
sidering our  present  state,  we  know  or  suppose  that  the 
conditions  of  these  events  are  present — in  other  words,  that 
these  events  are  possible ;  we  express  this  by  saying  that 
we  have  the  power,  capacity,  or  faculty  of  feeling,  perceiving, 

*  According  to  some,  the  word  I  ( je,  ich,  ego,  aham)  comes  from  the  root  ah, 
to  breathe,  and  denotes  the  inner  breath  ;  according  to  others,  it  comes  from  the 
root  gha,  ha,  which  signifies  this  one,  and  by  which  a  person  speaking  denotes  him 
self  to  his  listener. — Max  Mueller,  "  The  Science  of  Language." 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  249 

recollecting,  willing,  contracting  our  muscles.  Besides  these 
powers  common  to  all  men,  each  of  us  discovers  in  himself, 
by  a  similar  experience,  special  powers  peculiar  to  himself. 
Now,  when  we  consider  these  powers,  we  find  them  all  more 
or  less  permanent.  They  precede  events,  and,  in  general, 
survive  events.  They  last  intact  during  long  years,  some 
during  our  whole  life.  They  thus  form  a  contrast  with  tran- 
sitory events,  and  seem  the  essential  part  of  man.  In  this 
way  their  notion  is  attached  to  the  notion  of  the  persistent 
Ego ;  thereupon  this  Ego  ceases  to  appear  to  us  as  a  simple 
within;  it  becomes  furnished,  is  qualified,  and  determined; 
we  define  it  by  the  group  of  its  powers,  and,  if  we  allow 
ourselves  to  slip  into  metaphysical  error,  we  set  it  apart  as 
something  complete  and  independent,  invariably  the  same 
under  the  flow  of  its  events. 

VI.  Such  is  the  notion  of  the  Ego.  Illusory  in  the  meta- 
physical sense,  it  is  not  so  in  the  ordinary  sense ;  we  cannot 
pronounce  it  void  ;  there  is  something  corresponding  to  it, 
something  very  analogous  to  that  which,  according  to  our 
analysis,  constitutes  the  substance  of  bodies.  This  some- 
thing is  the  permanent  possibility  of  certain  events  under 
certain  conditions,  and  the  permanent  necessity  of  the  same 
events  under  the  same  conditions,  with  the  addition  of  a 
complementary  one,  all  these  events  having  a  common  and 
distinctive  character,  that  of  appearing  as  internal.  Thus 
we  are  entitled  to  say,  while  preserving  exactly  the  mean- 
ings of  our  words,  that  the  Ego  is  a  force  as  bodies  are — a 
force  which,  with  relation  to  them,  is  a  within,  as  they,  with 
relation  to  it,  are  a  without.  These  three  words,  force 
within,  without,  express  relations  only ;  nothing  more ;  at 
all  the  moments  of  my  life,  I  am  a  within,  capable  of 
certain  events  under  certain  conditions,  and  whose  events 
under  certain  conditions  are  capable  of  exciting  other  events 
in  itself  or  others.  This  is  what  endures  in  me,  and  this 
will  be  invariably  the  same  at  all  the  instants  of  my  ex- 
istence.— It  is  manifest  that  we  have  not  here  a  primitive 
notion.  It  has  precedents,  elements,  and  a  history,  and  we 
may  reckon  all  the  steps  of  the  involuntary  operation  which 
results  in  forming;  it. 


THE  .KNOWLEDGE   OF  MIND.  [BOOK.  III. 

It  is  necessary,  first,  that  we  should  have  recollections 
and  exact  recollections.  It  is  further  necessary  that,  by  the 
fixing  of  our  recollections,  our  events  should  appear  to  us 
as  a  continuous  thread.  It  is  then  necessary  that,  thanks 
to  the  abbreviations  of  memory,  the  particularities  of  our 
events  should  be  obliterated,  that  a  character  common  to 
all  the  elements  of  the  thread  should  predominate,  be  disen- 
gaged, be  isolated,  and  erected,  by  a  substantive  name,  into 
a  substance.  It  is  further  necessary  that  we  should  acquire 
the  idea  of  the  powers,  capacities,  or  faculties  of  this  sub- 
stance, therefore,  that  we  should  classify  our  events  accord- 
ing to  their  various  kinds,  that,  by  a  more  or  less  prolonged 
experience,  we  should  discover  their  external  and  internal 
conditions,  that,  stating  or  presuming  the  presence  of  con- 
ditions, we  should  conceive  these  events  as  possible,  and 
finally,  that  isolating  this  possibility,  we  should  attribute  it 
to  ourselves,  under  the  name  of  power,  capacity,  or  faculty. — 
The  idea,  then,  of  the  Ego,  is  a  product ;  many  variously  elabo- 
rated materials  concur  in  its  formation.  Like  every  mental 
or  organic  compound,  it  has  its  normal  form ;  but,  in  ordpr 
that  it  may  attain  this  form,  certain  materials  and  a  certain 
elaboration  are  required ;  with  a  very  slight  change  in  the 
elements  and  derangement  of  the  process,  the  form  is  de- 
viated from  and  the  final  result  is  monstrous.  Consequently 
the  idea  of  self  may  deviate  and  become  monstrous  ;  and, 
nearly  as  we  are  situated  to  ourselves,  we  may  deceive  our- 
selves in  many  ways  respecting  our  self. 

In  the  first  place,  certain  foreign  elements  may  introduce 
themselves  into  the  idea  we  have  of  it.  There  are  circum- 
stances in  which  a  series  of  imaginary  events  inserts  itself  in 
the  series  of  real  events ;  we  then  attribute  to  ourselves  what 
we  have  not  experienced  and  have  not  done. — In  the  waking 
state,  this  ocurrence  is  rare;  and  seldom  happens  except  with 
men  whose  imagination  is  over-excited.  I  have  mentioned 
the  story  of  Balzac,  who  described  one  day,  at  the  house  of 
Madame  de  Girardin,  a  white  horse  he  intended  to  present  to 
his  friend  Sandeau,  and  who,  a  few  days  afterwards,  in  the 
persuasion  that  he  had  actually  given  it,  inquired  of  Sandeau 
about  it.  It  is  plain  that  the  starting-point  of  an  illusion  like 


CHAP.  I.]  THE   KNOWLEDGE   OF  MIND.  25 1 

this  is  a  voluntary  fiction  ;  the  author  of  it  is  at  first  aware 
that  it  is  fictitious,  but  finally  forgets  it. — With  barbarous 
people,  in  uncultivated  and  childish  minds,  many  false  recol- 
lections thus  take  root.  Men  have  seen  a  very  simple  fact ; 
gradually,  when  it  is  distant,  in  thinking  of  it,  they  interpret 
it,  amplify  it,  provide  it  with  details,  and  these  imaginary  de- 
tails, becoming  incorporated  with  the  recollection,  end  by 
themselves  seeming  to  be  recollections.  The  majority  of 
legends,  and  religious  legends  especially,  are  formed  in  this 
way. — A  peasant,  whose  sister  had  died  abroad,  assured  me 
that  he  had  seen  her  soul  the  very  evening  of  her  death  ;  on 
inquiry  being  made,  this  soul  was  a  phosphorescence  produced 
in  a  corner  on  an  old  chest  of  drawers,  where  there  was  a  bot- 
tle of  spirits  of  wine  standing. — The  guide  of  a  friend  of  mine 
at  Smyrna  declared  that  he  had  seen  a  young  girl  carried 
through  the  air  in  full  daylight  by  enchantment ;  the  whole 
town  had  witnessed  the  miracle  ;  after  fifteen  hours  skilful 
questioning,  it  became  evident  that  all  the  guide  recollected 
was  having  seen  on  that  day  a  small  cloud  in  the  sky. — In 
fact,  what  constitutes  recollection  is  the  spontaneous  recoil 
of  a  representation  which  becomes  precisely  fixed  between 
certain  links  in  the  series  of  events  which  form  our  life.  When 
this  recoil  and  this  fixing  have  become  involuntary,  when  we 
no  longer  remember  that  they  were  at  first  purely  voluntary, 
when  finally  no  other  representation  is  projected  to  the  same 
spot  and  rises  there  to  form  an  obstacle,  the  false  recollection 
is  taken  for  true. 

All  these  conditions  are  met  with  in  dreams  ;  this  is  why  we 
have,  when  dreaming,  not  only  false  external  perceptions,  but 
also  false  recollections.*  I  have  noted  many  such  in  my  own 
case  ;  only  lately,  I  imagined  myself  to  be  in  a  d^aving-room 
turning  over  an  album  of  landscapes.  The  first  of  these  pic- 
tures represented  the  Polar  Sea,  a  great  expanse  of  blue  wa- 
ter, surrounded  with  icebergs.  At  this  moment,  I  perceived 


*  September  28,  1868.  M.  Maury  cites  many  false  recollections  which  he 
has  had  in  dreams.  "Le  Sommeil,"  etc.,  p.  211,  and  p.  70. — See  ante,  p.  65  (part 
i.  book  ii.  chap,  i.),  the  story  of  the  old  man  who  attributed  to  himself  the  travels 
he  had  read,  as  well  as  those  he  had  actually  made. 


352  THE   KNOWLEDGE   OF  MIND.  [BooKlII. 

the  artist  standing  before  me,  and  felt  myself  compelled  to 
praise  aloud  the  beauty  of  the  work ;  I  turned  over  the  pages, 
and  the  pictures  seemed  to  me  to  grow  more  and  more 
wretched,  and  suddenly  I  recollected  that,  a  year  ago,  I  had 
had  this  album  in  hand,  that  I  had  even  noticed  it  in  a  newspa- 
per that  my  article,  by  no  means  a  laudatory  one,  was  of  about 
thirty  or  forty  lines  on  the  third  column  of  the  second  page. 
On  this  recollection,  I  felt  so  confused  that  I  woke  up.  Now, 
observe  that  the  whole  dream  was  a  fiction  ;  but  the  recoil 
and  fixing  took  place  spontaneously  without  meeting  a  contra- 
dictory representation,  in  such  a  way  that  the  imaginary 
article  found  itself  affirmed. 

So,  again,  there  is  nothing  more  common  than  false  recol- 
lections in  cases  of  insanity,  and  especially  with  monomaniacs. 
Such  persons  form  a  romance  in  accordance  with  their  ruling 
passion,  and  this  romance  inserted  in  their  life  ends  by  com- 
posing in  their  eyes  all  their  past  life. — A  woman  whom  I 
have  seen  at  Salpetriere,  told,  with  perfect  precision  and  con- 
viction, a  story  according  to  which  she  was  noble  and  wealthy. 
Her  real  name  was  Virginie  Silly,  and  she  called  herself 
Eugenie  de  Sully.  To  believe  her,  her  parents  had  purposely 
lost  her  seven  or  eight  times,  and  her  mother  had  finally  sold 
her  to  a  mountebank,  with  whom  she  remained  two  years. 
Before  1848,  she  had  interviews  with  Louis  Philippe  and 
made  reports  to  him  on  the  Casino,  the  Chaumiere,  the 
Ranelagh,  and  the  hospitals.  "  I  was,"  she  said,  "  commis- 
sary-reporter to  his  Majesty,  and  the  King  gave  me  large 
sums."  Later  on,  when  she  was  living  in  the  Rue  Poisson- 
niere,  the  Emperor  came  to  listen  to  her  conversation  from 
behind  a  screen,  and  caused  her  to  be  locked  up.  One  of  her 
uncles,  a  slave  dealer  in  Chili,  left  her  six  millions ;  she  has 
still  a  quarter  of  a  million  in  the  Bank.  But  she  has  been 
robbed  of  her  papers  and  parchments,  and  in  their  stead  has 
been  left  a  false  register  of  birth,  according  to  which  she  is 
poor  and  of  humble  origin.*— Another  woman,  in  the  service 
of  M.  Metivier,  and  the  daughter  of  a  porter  in  a  public  office, 


*  From  a  note  of  a  Lecture  by  M.  Baillarger,  at  the  Salpetriere,  in  1856.  The 
Professor  questioned  the  patients  in  the  presence  of  his  class. 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  353 

being  young  and  pretty,  imagined  that  the  minister  frequently 
noticed  her,  and  alleged  that  he  had  communicated  with  her 
through  a  procuress.  On  this,  her  lover,  who  was  a  clerk  in* 
the  office,  broke  off  the  engagement.  She  married  a  work- 
man, became  pregnant,  was  confined,  and,  in  the  meantime, 
the  minister  died ;  she  then  announced  that  he  had  left  her 
by  will  two  hundred  thousand  francs.  Her  false  recollections 
were  so  clear  that  her  lover  abandoned  her,  and  her  husband 
almost  believed  her.* — In  somnambulism  and  hypnotism,  the 
patient  who  has  become  extremely  sensible  to  suggestion,  is 
subject  to  similar  illusions  of  memory;  he  is  told  that  he  has 
committed  such  and  such  a  crime,  and  his  figure  at  once  ex- 
presses horror  and  dismay.  Ordinary  recollections  no  longer 
present  themselves,  or  are  too  feeble  to  exercise  their  ordinary 
power  of  repression ;  in  the  absence  of  the  normal  counter- 
poise, the  simple  conception  becomes  an  affirmative  concep- 
tion, and  the  patient  recollects  murders  which  he  has  not 
committed. 

Other  cases  present  the  inverse  illusion.  We  then  no 
longer  deceive  ourselves  by  addition,  but  by  exclusion ;  in- 
stead of  inserting  in  our  series  events  which  do  not  belong 
to  us,  we  cast  out  of  our  series  events  which  are  really  ours. — 
This  is  the  error  into  which  we  fall  respecting  colors  and 
sounds  ;  its  mechanism  has  been  described.  These,  in  them- 
selves, are  sensations,  like  those  of  heat  or  taste ;  but  as  they 
are  repulsed  from  our  nervous  surface,  they  appear  detached 
from  us ;  by  this  alienation,  sound  appears  as  an  external 
event,  and  color  as  a  quality  of  a  body  other  than  ourselves. — 
This  error  is  normal,  and  we  have  shown  in  what  way  it  is 
useful.  But  there  are  others  which  are  abnormal,  and  brirfg 
disturbance  into  all  our  conduct ;  these  are  the  hallucinations 
termed  psychical ;  f  in  such  cases,  the  patient  alienates  and 
refers  to  others  thoughts  which  are  his  own  ;  he  understands 
by  thought,  he  hears  "  secret  internal  voices ;  "  they  speak  to 
him  "  silently;  "  he  sees  "  invisibly."  The  wife  of  an  English 
officer  at  Charenton  spoke  of  a  sixth  sense  by  which'  she 


*  See  Leuret,  "  Fragments  Psycho! ogiques,"  for  an  analogous  case  of  a  mad- 
nan  called  Benoit  (p  64). 

f  Baillarger,  "  Des  Hallucinations,"  part  i. 

23 


354  THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 

heard  voices ;  it  was  "  the  sense  of  thought." — When  we 
question  such  patients,  they  reply  that  the  word  voice  of 
which  they  avail  themselves  is  very  inappropriate,  and  that 
they  use  it  by  way  of  metaphor,  for  want  of  a  better  word  ; 
the  voice  has  no  tone,  it  does  not  seem  to  come  from  the 
outer  world  as  in  ordinary  cases ;  mystics  have  already  made 
this  distinction,  and  oppose  "intellectual  speech  and  voices" 
which  their  soul  seizes  without  the  intervention  of  the  organs 
of  sense,  to  bodily  voices  which  they  perceive  in  the  same 
way  as  in  ordinary  life.  Blake,  the  poet  and  engraver,  who 
called  up  the  illustrious  dead,  conversed  with  them  "  soul  to 
soul,"  and,  as  he  said,  "  by  intuition  and  magnetism." — It  is 
easy  to  recognize  that  the  ideas  which  such  persons  attribute 
to  others  belong  to  themselves.  A  person  talking  with  Blake 
begged  him  to  ask  Richard  III.  if  he  professed  to  justify  the 
murders  he  had  committed  during  his  life.  "  Your  question," 
said  Blake,  "has  already  reached  him.  .  .  .  We  have  no  need 
of  words.  This  is  his  answer,  only  it  is  somewhat  longer 
than  he  gave  it  me,  for  you  would  not  understand  the  lan- 
guage of  spirits. — He  says  that  what  you  call  murder  and 
carnage  is  all  nothing ;  that  in  slaughtering  fifteen  or  twenty 
thousand  men  you  do  no  wrong,  for  what  is  immortal  of  them 
is  not  only  preserved  but  passes  into  a  better  world,  and  the 
man  who  reproaches  his  assassin  is  guilty  of  ingratitude,  for 
it  is  by  his  means  that  he  enters  into  a  happier  and  more 
perfect  state  of  existence.  But  do  not  interrupt  me,  he  is 
now  in  a  very  good  position,  and  if  you  say  anything  more 
he  will  go."  It  is  evident  that  Blake  imputed  his  own 
theories  and  dreams  to  Richard  III. ;  the  person  he  imagined 
was  an  echo  which  sent  him  back  his  own  thought. — A  mad- 
woman played  incessantly  at  even  or  odd  with  an  absent  per- 
son whom  she  believed  to  be  the  prefect  of  police ;  before 
playing,  she  looked  at  the  coins  she  had  in  her  hand,  and 
thus  knew  their  number ;  the  prefect,  therefore,  always 
guessed  wrong,  and  never  failed  to  lose ;  later  on,  she  neg- 
lected her  preliminary  examination;  and  then,  the  prefect 
sometimes  lost,  and  sometimes  won. — It  is  evident  that,  at 
first,  she  herself  fabricated,  without  suspecting  it,  the  error 
s'.ie  attributed  to  the  prefect. 


C:IAP.  I.]  THE  KNOWLEDGE   OF  MIND.  355 

The  starting  point  of  these  illusions  is  not  hard  to  distin- 
guish ;  we  find  it  in  the  process  of  mind  of  the  dramatic  au- 
thor, the  novelist,  of  every  person  of  lively  imagination ;  in 
the  midst  of  a  mental  monologue,  there  springs  up  an  address, 
an  answer,  a  kind  of  internal  person  rises  and  addresses  us  in 
the  second  person :  "  Rentre  en  toi-meme,  Octave,  et  cesse 
de  te  plaindre." — Now  suppose  that  these  addresses,  these 
answers,  while  remaining  mental,  are  wholly  unforeseen  and 
involuntary — a  thing  which  often  happens.  Suppose  they 
comprise  strange  and  sometimes  terrible  ideas,  that  the 
patient  cannot  excite  them  at  will,  that  he  undergoes  them, 
that  he  is  beset  by  them.*  Suppose,  in  a  word,  that  these 
discourses  are  well  connected,  indicate  an  intention,  impel 
the  patient  in  one  or  another  direction,  towards  devotion  or 
towards  vice.  He  will  be  tempted  to  attribute  them  to  an 
invisible  speaker,  especially  if  the  religious  atmosphere  in 
which  he  lives,  and  his  own  special  creed,  authorize  his  fabri- 
cating such  a  speaker.  The  whole  series  which  constitutes 
the  Ego  is  thus  cut  into  two  parts,  because  the  two  partial 
series  which  compose  it  present  distinct  or  even  opposite 
characters.  Sometimes,  when  the  second  has  nothing  extra- 
ordinary about  it,  the  patient  still  attributes  it  to  himself,  and 
believes  himself  to  be  double.  "  I  am  led  to  believe,"  says  a 
sufferer  from  hallucinations,  "  that  I  have  always  had  within 
me  a  double  thought,  one  of  which  controls  the  actions  of 
the  other."  "  There  is,"  says  another  patient,  "  as  it  were  a 
second  myself  who  inspects  all  my  actions  and  words,  like  an 
echo  which  repeats  everything."  A  third,  recovering  from  a 
fever,  "  believed  himself  formed  of  two  individuals,  one  of 
which  was  in  bed,  while  the  other  walked  about ;  although 
he  felt  no  appetite,  he  ate  largely,  having,  as  he  said,  two 
bodies  to  support. "f — At  other  times,  the  second  series  is 
referred  to  another  person,  especially  when  the  ideas  it  con- 
tains are  out  of  proportion  to  those  which  make  up  the  first 


*  See  the  whole  autobiography  of  Bunyan,  the  author  of  the  "  Pilgrim's  Pro- 
gress."— Also  the  eloquent  and  sublime  conversations  of  Tasso  with  his  familiar 
genius,  recorded  by  Manso. — So  again,  the  warnings  given  to  Socrates  by  an 
internal  voice. 

f  Griesinger,  p.  93,  and  Baillarger,  op.  cit.  passim. 


356  THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 

series.  Thus  were  formed  the  demon  of  Socrates,  and  the 
familiar  genius  of  Tasso. — Usually,  after  a  time,  sensorial 
hallucination  comes  in  to  complete  psychical  hallucination. 
The  internal  mental  voices  become  physical  and  external. 
"  At  first,  according  to  patients,  it  was  something  ideal  and 
like  a  spirit  speaking  in  them ;  now,  they  actually  hear 
speech ; "  the  voices  are  clear  or  indistinct,  deep  or  high, 
melodious  or  screeching.  I  have  already  mentioned  the 
case  of  Theophile  Gautier,  and  how,  passing  once  before  the 
Vaudeville,  a  phrase  printed  on  the  notice-board  fastened  it- 
self upon  his  recollection,  how,  in  spite  of  himself,  he  inces- 
santly repeated  it,  how  after  some  time  it  ceased  to  be 
simply  mental,  and  seemed  to  proceed  from  a  bodily  throat, 
with  distinct  tone  and  accent ;  it  revisited  him  thus,  at  in- 
tervals and  unexpectedly,  and  this  lasted  several  weeks. 
Suppose  a  mind  preoccupied,  beset  with  fears,  assume  that 
the  voice  pronounces,  not  only  a  single  monotonous  phrase, 
but  a  series  of  threatening  and  appropriate  speeches,  and  we 
have  the  case  of  Luther  at  the  Wartburg,  when  he  disputed 
with  the  devil.  The  mental  words  have  excited  in  the  sen- 
sory centres  of  the  encephalon  corresponding  sensations  of 
hearing,  and  henceforth,  detached  in  this  double  sense  from 
the  Ego,  they  are  imputed  to  an  interlocutor. 

These  illusions  are  partial  only ;  there  are  total  illusions, 
in  which  the  series  of  our  events  is  replaced  by  a  strange 
series.  Peter  imagines  himself  Paul,  and  acts  on  the  belief. 
Here  again,  the  starting  point  of  the  error  is  in  a  well-known 
process  of  the  mind,  that  of  the  novelist  or  author  who  puts 
himself  in  the  place  of  his  characters,  adopts  their  passion, 
and  experiences  their  emotions. — This  operation  is  nowhere 
so  clearly  seen  as  in  hypnotism ;  the  attention  of  the  patient 
is  then  limited  and  concentrated,  and  rests  only  on  one  series 
of  ideas  ;  this  alone  is  developed ;  all  others  are  benumbed, 
and,  for  the  time,  incapable  of  reviving ;  consequently  ordin- 
ary recollections  are  missing  and  no  longer  exercise  their  re- 
pression ;  the  illusion  which,  in  the  author  and  novelist,  is 
upset  at  every  moment,  is  now  no  longer  checked  and  follows 
its  course.*  "  A.  B.  was  asked  his  name,  he  answered  rightly, 

*  "  Annales  Medico-psychologiques,"  4  ""  Serie,  vi.  428. — Dr.   Hack  Tuke, 
"  De  la  Foiie  Artificielle." 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  357 

without  hesitation.  When  hypnotized  and  in  the  state  of 
coma  (being  capable  of  holding  himself  upright  and  in  appear- 
ance wide  awake,  though  with  a  strange  wandering  air  as  in 
somnambulism)  it  was  strongly  suggested  to  him  that  he  was 
Richard  Cobden.  A  few  seconds  afterwards  he  was  asked 
his  name.  He  answered  at  once,  and  without  hesitation, 
'  Richard  Cobden.' — '  Are  you  perfectly  sure  of  it?  ' — '  Yes,' 
he  answered.  —  Similar  experiments  tried  with  different 
names,  on  various  other  occasions,  had  always  the  same  re- 
sults.— During  the  state  of  normal  wakefulness,  the  subjects 
experimented  on  gave  their  proper  names  as  soon  as  they 
were  asked.  On  the  contrary,  if  during  the  fitting  period  of 
hypnotic  sleep  the  name  of  a  king  was  suggested  to  them, 
not  only  were  they  impelled  to  say  that  it  was  their  name, 
but  they  felt  and  acted  in  a  way  which  manifested  their  convic- 
tion that  they  were  kings" 

This  state,  instead  of  being  transient,  may  become  fixed ; 
this  is  frequent  in  the  asylums,  and  is  often  met  with  in 
periods  of  religious  exaltation. — A  quartermaster  in  Crom- 
well's army,  James  Naylor,  believed  himself  God  the  Father, 
and  was  worshipped  by  many  enthusiastic  women.  He  was 
tried  by  Parliament,  and  sentenced  to  the  pillory. — We  find, 
in  asylums,  lunatics  who  believe  themselves  Napoleon,  the 
Virgin  Mary,  the  Messiah,  or  some  other  person.  One  of 
them  named  Dupre,  a  patient  of  Leuret,  believed  and  said 
that  he  was  at  once  Napoleon,  Delavigne,  Picard,  Andrieux, 
Destouches,  and  Bernardin  de  Saint-Pierre. — A  woman  called 
Catherine,  mentioned  by  Leuret,  is  no  longer  herself;  she 
does  not  call  herself  Catherine ;  there  is  a  rupture  be- 
tween her  past  and  present ;  she  only  speaks  of  herself  in  the 
third  person,  saying  "  the  person  of  myself." — Others  are 
transformed  into  animals.  "  There  was  a  man  of  Padua," 
says  Wier,  "  in  1541,  who  believed  himself  to  be  changed  into 
a  wolf,  and  ran  about  the  country  attacking  and  killing  all 
he  met.  After  many  difficulties,  they  contrived  to  seize 
him.  He  said  boldly  to  those  who  arrested  him  :  '  I  am 
really  a  wolf,  and  if  my  skin  does  not  look  like  a  wolfs  skin, 
it  is  because  it  is  turned  and  the  hair  is  inside.' — In  order  to 
assure  themselves  of  the  fact,  they  wounded  the  wretched 


THE    KNOWLEDGE   OF  MIND.  [BOOK  III. 

man  in  different  parts  of  his  body,  and  tore  off  his  arms  and 
legs." — If  the  patient  experiences  false  sensations,  through 
hypnotism  or  illness,  he  may  come  to  form  the  most  eccentric 
ideas  of  his  body,  and  therefore  of  his  personality. — "  Among 
a  number  of  hypnotized  women,"  says  Dr.  Elliotson,  "  one 
imagined  that  she  was  made  of  glass,  and  was  afraid  that  she 
might  become  broken ;  another  that  she  was  no  bigger  than 
a  grain  of  wheat ;  another  that  she  was  dead."  And  so,  some 
insane  persons  are  convinced  that  their  body  is  made,  of  wax, 
of  butter,  of  wood,  and  act  accordingly.  Leuret  mentions 
men  who  believe  themselves  changed  into  women,  and  wo- 
men who  believe  themselves  men. — A  soldier  whose  skin  had 
become  insensible,  believed  himself  to  have  been  dead  since 
the  battle  of  Austerlitz,  where  he  received  a  wound.  "  When 
he  was  asked  as  to  his  health,  he  said — '  You  want  to  know 
how  Father  Lambert  is  ?  But  there  is  no  Father  Lambert ; 
a  cannon-ball  killed  him  at  Austerlitz  ;  what  you  see  here  is 
not  him  ;  it  is  a  wretched  machine  made  to  look  like  him ; 
you  ought  to  ask  them  to  make  a  better  one.'  " — In  speak- 
ing of  himself  he  never  said  me,  but  always  it* 

In  short,  the  conception  which  I  have  of  myself  at  any 
given  moment  is  an  abbreviatory  and  substitutive  name, 
sometimes  my  name,  sometimes  the  word  /  or  me,  both  of 
them  mentally  pronounced.  If  I  dwell  on  this  name,  it  will, 
in  the  normal  state,  call  up  in  me,  by  association,  its  equiva- 
lent, that  is  to  say  the  series  of  my  actual  and  interior  events, 
joined  with  the  numerous  series  of  possible  events  of  which  I 
am  actually  capable.  But  this  principal  association,  being 
an  acquired  one,  may  be  lost ;  and  so  it  is  with  the  secondary 
associations  which  solder  together  in  my  mind  the  various 
fragments  of  the  whole  series.  If  an  extrinsic  fragment  or  an 
extrinsic  series  then  comes  to  intercalate  itself  in  the  empty 
place,  the  patient  will  be  mistaken  about  himself.  We  have 
just  seen  the  principal  conditions  of  this  transposition. 

*  Analogous  illusions  occur  in  dreams.  M.  Charma  dreamed  once  that  he 
was  aide-de-camp  to  Henry  IV. ;  another  time  that  he  was  Voltaire. — Dr.  Mac- 
nish  dreamed  that  he  was  a  pillar  of  stone,  and  saw  all  that  passed  around  him. 
— De  Quincey,  the  opium-eater,  dreamed  that  he  was  the  idol  in  a  Brahminical 
temple,  etc. 


CHAP.  I.]  THE  KNOWLEDGE  OF  MIND.  359 

Sometimes  the  energy  of  the  normal  associations  is  weakened, 
as  in  sleep  and  hypnotism  ;  the  link  which  binds  my  name  to 
the  word  /  is  weakened  ;  consequently,  a  persistent  sugges- 
tion is  capable  of  substituting  for  my  name  that  of  another ; 
henceforward  this  name  with  the  whole  series  of  events  of 
which  it  is  the  equivalent  is  called  up  m  me  as  soon  as  the 
word  /  reverts  mentally,  and  henceforward  I  am,  in  my  own 
eyes,  some  other  person — Richard  Cobden,  or  Prince  Albert. 
— Sometimes  the  energy  of  the  normal  associations  is  con- 
quered by  a  greater  force.  The  pure  conception  which, 
repressed  by  the  series  of  recollections,  was  at  first  checked 
in  its  evolution,  now  accomplishes  its  development  in  accor- 
dance with  its  hallucinatory  tendency.  Incessantly  repeated, 
with  daily  increased  vividness,  maintained  by  a  ruling  passion, 
by  vanity,  love,  or  religious  scruples,  sustained  by  false  sen- 
sations ill  interpreted,  confirmed  by  a  group  of  suitable 
explanations,  it  assumes  a  definite  ascendancy,  annuls  con- 
tradictory recollections ;  being  no  longer  negatived,  it  is 
pronounced  affirmative  ;  and  the  fiction,  which  was  at  first 
declared  a  fiction,  seems  a  true  story. — Thus,  our  idea  of 
our  person  is  a  group  of  co-ordinated  elements  whose  mutual 
associations,  ceaselessly  attacked  and  ceaselessly  victorious, 
are  maintained  during  our  waking  hours  and  reason,  as  the 
composition  of  an  organ  is  maintained  during  health  and 
life.  But  madness  is  always  hovering  near  the  mind,  as 
illness  is  always  hovering  near  the  body;  for  the  normal 
combination  is  a  victory  only  ;  it  results  from  and  is  renewed 
by  the  continual  defeat  of  the  contrary  forces.  Now,  these 
last  are  always  present ;  an  accident  may  give  them  the 
preponderance ;  there  is  but  little  required  to  enable  them  to 
assume  it ;  a  slight  alteration  in  the  proportion  of  the  ele- 
mentary affinities  and  in  the  direction  of  the  constructing 
process  would  bring  on  a  degeneracy.  Morally  or  physically, 
the  form  we  term  regular  may  indeed  be  the  most  frequent, 
but  it  is  through  an  infinite  number  of  possible  deformations 
that  it  is  produced. — We  may  compare  the  silent  elaboration 
of  which  consciousness  is  the  ordinary  result  to  the  progress 
of  the  slave,  who,  after  the  games  of  the  circus,  crossed  the 
length  of  the  arena,  among  wearied  lions  and  glutted  tigers, 


360  THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 

bearing  in  his  hand  an  egg ;  if  he  arrived  safely,  he  received 
his  freedom.  So  passes  the  mind  through  the  confusion  of 
monstrous  deliria  and  yelling  madness,  almost  always  with 
impunity,  to  settle  itself  in  accurate  consciousness  and  exact 
recollection. 

VII.  How  does  it  happen  that  the  slave  arrives  so  fre- 
quently at  his  destination  ?  Whence  comes  it  that  our  present 
recollections  almost  invariably  correspond  to  past  sensations  ; 
that  the  place  we  assign  to  these  sensations  is  almost  invaria- 
bly that  which  they  actually  occupied ;  that  it  scarcely  ever 
happens  that  the  chain  of  our  events  lets  slip  one  of  its  own 
links  or  receives  a  link  that  does  not  belong  to  it ;  that  the 
group  o'f  past,  present,  and  possible  events,  of  which  we  com- 
pose our  personality  is,  almost  always,  really  the  group  of 
events  which  have  happened  to  us,  are  passing  within  us,  and 
which  may  occur  to  us?  By  what  adjustment  is  the  almost 
invariable  accordance  of  our  thought  and  our  being  set  up  ? — 
It  must  be  understood  that  we  do  not  here  undertake  to  dem- 
onstrate the  veracity  of  memory  ;  the  thing  is  impossible.  In 
fact,  such  a  proof  would  be  reasoning  in  a  circle  ;  for,  if  mem- 
ory be  accurate,  it  is  through  certain  laws  which  accommodate 
the  recollection  to  its  object ;  now  these  laws  can  only  be  ob- 
tained by  us  from  the  facts  we  observe  and  which  we  remem- 
ber for  the  purpose  of  comparing  them ;  so  that,  in  order  to 
prove  the  fidelity  of  memory,  it  would  first  be  necessary  to 
admit  the  fidelity  of  memory.  We  do  admit  it  and  without 
much  hesitation,  if  not  upon  a  direct  demonstration,  at  least 
after  a  host  of  innumerable  confirmations,  and  as  an  hypoth- 
esis justifying  the  whole  of  the  experience,  verifications,  and 
previsions  of  mankind. — This,  when  settled,  is  enough  to  ex- 
plain it,  and  we  have  but  to  regard  the  described  mechanism 
to  comprehend  the  almost  infallible  accuracy  of  its  working. 

In  the  first  place,  what  constitutes  recollection  is  a  present 
image  which  appears  a  past  sensation,  and  which,  by  the  re- 
pressive contradiction  of  present  sensations,  finds  itself  con- 
strained to  an  apparent  recoil.  Now,  we  have  seen  fhat  the 
sensation,  after  it  has  ceased,  has  the  property  of  reviving  by 
its  image ;  as  a  general  rule,  almost  every  clear  and  circum- 
stantial image  supposes  an  antecedent  sensation ;  so  that,  if 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND  36  r 

our  judgment  is  invariably  false  in  itself,  it  is  almost  invaria- 
bly true  by  correspondence.  We  invariably  deceive  ourselves 
by  taking  the  present  image  for  a  distant  sensation  ;  but,  as  a 
rule,  the  distant  sensation  was  produced.  If  the  image  by  its 
presence  excites  a  constant  illusion  which  forms  recollection, 
on  the  other  hand,  it  compensates  this  illusion  by  its  origin, 
which  is  almost  invariably  an  anterior  sensation ;  if  I  may 
venture  to  say  so,  it  rectifies,  on  the  one  hand,  the  error  into 
which  it  leads  us  on  the  other. 

Secondly,  what  situates  the  repulsed  image  before  some 
particular  sensation  is  the  presence  of  that  sensation  or  the 
recall  of  that  sensation  by  its  image.  Now,  as  we  saw  in 
proving  the  laws  which  govern  the  revival  of  images,  my  pres- 
ent sensation  tends  to  call  up  the  image  of  the  preceding  sen- 
sation contiguous  to  it ;  and,  in  general,  images  of  sensations 
which  have  been  contiguous,  tend  to  call  each  other  up ; 
whence  it  follows  that  the  image  of  a  past  sensation  tends  to 
call  up  the  images  of  the  anterior  and  posterior  sensations 
which  were  contiguous  to  it.  Consequently,  the  abbreviatory 
image  of  a  long  series  of  sensations,  operations,  and  actions, 
that  is  to  say  of  a  considerable  fragment  of  my  life,  tends  to 
call  up  abbreviatory  images  of  the  anterior  and  posterior  frag- 
ments.— But  we  have  shown  that  the  posterior  sensation, 
whether  by  itself  or  by  its  image,  exerts  on  the  image  of  the 
preceding  sensation  a  contradiction  which  comes  to  an  end 
when  its  commencement  meets  with  the  end  of  its  antago- 
nist, whence  it  happens  that  the  repulsed  image  appears  fast- 
ened by  its  end  to  the  commencement  of  the  image  or  sensa- 
tion repulsing  it.  Consequently,  when  the  image  of  a  past 
sensation  calls  up  the  image  of  the  posterior  sensation  and 
the  image  of  the  anterior  one,  it  is  repulsed  by  the  first,  it  re- 
pulses the  second,  it  connects  itself  by  its  end  with  the  com- 
mencement of  the  first,  by  its  commencement  with  the  end 
of  the  second,  and  thus  becomes  fixed  between  the  two. 
Whenever  the  three  images  come  in  to  override  on  another, 
the  two  repulsions  act  in  the  manner  indicated,  the  mechan- 
ism which  situates  them  acts  so  as  to  arrange  them  in  a  line, 
as  soon  as  the  law  of  mutual  evocation  arouses  them  togeth- 
er. They  thus  contract,  with  relation  to  one  another,  an  ap- 


362  THE  KNOWLEDGE   OF  MIND.  [Boox  III. 

parent  order  which  corresponds  to  the  real  order  of  the  sen- 
sations of  which  they  are  the  remains.  The  contiguity  of  two 
sensations,  one  preceding,  the  other  following,  the  reciprocal 
calling  up  of  the  image  of  the  one  by  the  image  of  the  other, 
the  apparent  joining  of  the  two  images,  a  joining  such  that, 
while  both  appear  as  sensations,  the  first  appears  anterior  to 
the  second :  these  are  all  the  steps  of  the  operation ;  hence 
we  see  that  the  real  date  of  a  sensation  determines  the  appa- 
rent date  of  its  image.  Here  again,  the  agreement  is  estab- 
lished by  a  correspondence. 

As  a  general  rule,  not  only  does  every  precise  and  detailed 
image  presume  an  antecedent  sensation,  but  every  precise  and 
detailed  image,  which  is  joined,  in  appearance,  to  another  pos- 
terior one,  presumes  that  the  sensation  whence  it  was  derived 
was  joined  in  the  same  manner,  but  in  reality,  to  the  sensa- 
tion which  the  other  repeats.  If  its  attachment,  then,  inva- 
riably excites  an  illusion  by  compelling  the  other  to  appear 
anterior,  almost  invariably  does  its  origin — the  sensation  pos- 
terior to  the  sensation  of  which  the  other  is  the  echo — repair 
this  error. 

Thus,  the  thread  of  our  events  is  formed  in  our  memory ; 
at  every  moment  we  look  back  on  a  portion  ;  a  day  never 
passes  without  our  having  frequently  reverted  back,  and 
sometimes  far  back  in  the  chain,  sometimes,  by  means  of 
abbreviatory  processes,  to  events  separated  from  the  present 
moment  by  many  months  and  many  years.  Associations  so 
repeated  are  continually  becoming  more  tenacious  ;  our  past 
is  a  line  which  we  never  weary  of  tracing  over  and  refreshing 
with  ink. — Classes  become  established  among  these  events  ; 
they  group  themselves  spontaneously  according  to  their 
resemblances  and  differences ;  the  most  frequent,  the  acts  of 
walking,  grasping  with  the  hand,  lifting  a  weight,  feeling, 
touching,  smelling,  tasting,  seeing,  hearing,  recollecting,  fore- 
seeing, willing,  are  collected  each  under  a  name  ;  we  conceive 
them  as  possible  to  us,  and  these  possibilities,  incessantly 
verified  and  limited  by  experience,  constitute  our  powers  or 
faculties.  There  is  no  one  of  them  whose  presence,  range, 
and  limits  may  not  at  any  hour  be  manifested  to  us,  so  that 
our  idea  is  associated  with  the  idea  of  self  by  links  which  are 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  363 

hourly  re-forged  and  strengthened. — Add  to  the  recollection 
of  my  events  and  to  the  idea  of  my  powers  a  last  idea 
similarly  renewed  and  strengthened  at  every  moment  by 
experience,  that  of  the  body  which  I  call  mine,  and  which 
is  distinguished  by  sharply  divided  characteristics  from  all 
others,  being  the  only  one  which  answers  to  my  touch  by  a 
sensation  of  contact,  the  only  one  whose  changes  excite 
sensations  in  me  without  an  intermediate,  the  only  one  in 
which  my  will  is  capable  of  exciting  changes  without  an 
intermediate,  the  only  one  in  which  the  sensations  I  ascribe 
to  myself  appear  to  be  situated.  All  this  group  of  true  ideas 
and  exact  recollections  form  a  singularly  solid  network.  It 
requires,  then,  a  great  accumulation  of  forces  to  tear  from  it 
any  portion  really  belonging  to  it,  or  to  insert  in  it  any  por 
tion  extrinsic  to  it. — In  fact,  these  transpositions  are  rare ; 
they  are  principally  met  with  when  an  organic  change,  like 
sleep  or  hypnotism,  loosens  the  meshes  of  the  network,  when 
an  inveterate,  predominant  passion,  fortified  by  psychical  or 
sensorial  hallucinations,  at  last  wears  away  some  thread  of 
the  tissue,  substitutes  another  thread,  and,  gaining  step  by 
step,  sets  a  fictitious  web  in  the  place  of  the  natural  web. 
But,  as  woven  under  ordinary  conditions,  the  web  is  good, 
and  its  threads  correspond,  by  their  presence,  by  their  di- 
versities, by  their  apparent  dates,  by  their  connections,  to 
the  presence,  the  diversities,  the  real  dates,  the  connections 
of  the  real  facts ;  this  is  because  the  real  facts  themselves 
have  woven  it.  The  mind  resembles  a  loom  ;  every  event  is 
an  impulse  which  sets  it  in  action,  and  the  fabric  which  issues 
from  it,  transcribes  by  its  structure  the  order  and  kind  of 
the  impulses  which  the  machine  has  received. 

VIII.  When,  by  the  experiences  of  touch,  of  the  educated 
sight,  and  the  other  senses,  we  have  acquired  a  sufficiently 
precise  and  complete  idea  of  our  body,  and  there  is  associated 
to  this  idea  that  of  a  within  or  subject,  capable  of  sensations, 
recollections,  perceptions,  volitions,  and  the  rest,  we  make  a 
further  step.  Among  the  innumerable  bodies  surrounding  us, 
there  are  many  which  more  or  less  resemble  our  own.  In 
other  words,  if  we  explore  them,  they  excite  in  us  sensations 
of  contact,  resistance,  temperature,  color,  and  of  tactile  and 


364  THE  KNOWLEDGE   OF  MIND.  [BOOK  III. 

visual  shape  and  size,  nearly  analogous  to  those  which  we  ex- 
perience when  we  take  cognizance  by  the  eye  and  hand  of 
our  own  body.  Thus  the  group  of  images  by  which  we  pic- 
ture to  ourselves  these  bodies  is  very  similar  to  the  group  of 
images  by  which  we  represent  to  ourselves  our  own. — Conse- 
quently, in  accordance  with  the  law  of  the  association  of  im- 
ages, when  the  first  group  rises  in  us,  it  must,  like  the  other, 
call  up  the  idea  of  a  subject  or  within,  capable  of  sensations, 
perceptions,  volitions,  and  other  similar  operations.  This  is 
the  spontaneous  suggestion  or  induction  ;  it  is  gradually  con- 
firmed and  rendered  precise  by  numerous  verifications. — In 
the  first  place,  we  observe  that  this  body  moves,  not  always 
in  the  same  manner,  in  correspondence  to  a  mechanical  im- 
pulse, but  variously,  without  external  impulsion,  towards  an 
end,  seemingly  directed  by  a  purpose,  just  as  our  own  body 
is  moved  and  directed,  which  leads  us  to  conjecture  that  in  its 
case  there  are  intentions,  preferences,  motive  ideas,  a  will,  as 
with  us.* — Secondly,  and  especially  if  it  be  an  animal  of  a 
higher  species,  we  see  it  perform  a  number  of  actions  analo- 
gous to  what  we  find  in  ourselves,  such  as  crying,  walking, 
running,  sleeping,  drinking,  eating,  all  of  which  leads  us  to  im- 
pute to  it  perceptions,  ideas,  recollections,  emotions,  desires, 
similar  to  those  of  which  these  actions  are  in  our  cases  the  ef- 
fects.— Lastly,  we  put  our  conjectures  to  the  proof.  Having 
recognized  in  our  own  cases  the  antecedents  and  consequents 
of  fear,  pain,  joy,  and,  in  general,  of  some  particular  internal 
state,  we  reproduce  for  it  these  antecedents,  or  prove  in  it 
these  consequents,  and  conclude  that  the  internal  and  inter- 
mediate state,  which,  visible  in  our  cases,  is  invisible  in  its 
case,  must  have  been  produced  in  its  case  as  in  our  own.  We 
know  that,  in  our  cases,  a  blow  with  a  stick  is  the  antecedent  of 
a  pain,  and  that  a  cry  is  the  consequent  of  the  pain.  We 
strike  a  dog,  and  at  once  hear  it  give  a  cry ;  between  this  con- 


*  The  child  is  angry  with  a  balloon  or  tuft  of  down  which  floats  about  capri- 
ciously, and  will  not  allow  him  to  seize  it. —  In  primitive  times,  men  considered 
the  sun,  the  rivers,  as  animated  beings. — The  savage  takes  a  watch  which  ticks  and 
whose  hands  move,  for  a  little  round  tortoise. — A  movement  which  appears  spon- 
taneous, invariably  suggests  the  idea  of  a  will,  and  especially  if  it  appears  to  have 
an  object 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIND.  365 

dition  of  pain  and  this  sign  of  pain,  both  of  which  we  clearly 
perceive,  we  insert,  by  conjecture,  a  pain  similar  to  what  we 
should  ourselves  have  felt  in  such  a  case. — Thanks  to  these 
suggestions  and  these  continual  verifications,  the  outer  world 
which  so  far  has  been  peopled  with  bodies  only,  is  also  peo- 
pled with  souls,  and  the  solitary  Ego  conceives  and  affirms 
around  it  a  multitude  of  beings  more  or  less  similar  to  itself. 
IX.  All  these  cognitions  are  composed  of  the  same  ele- 
ments joined  together  according  to  the  same  law.  Whether  it 
be  a  question  of  a  body,  of  ourselves,  of  another  animated  being, 
whether  the  operation  be  termed  external  perception,  act  of 
consciousness,  recollection,  induction,  pure  conception,  our  op- 
eration is  invariably  a  mass  of  which  the  molecules  are  sensa- 
tions and  images  joined  to  images  agglutinated  into  partial 
groups  which  mutually  call  each  other  up. — A  couple  is  formed 
by  the  aggregation  of  two  molecules  ;  to  this  is  attached 
another  couple,  to  these  combined,  others  combined,  and  so 
on,  till  at  last  the  vast  compound  we  term  the  idea  of  an  indi- 
vidual, the  idea  of  this  tree,  of  myself,  of  this  dog,  of  Peter,  or 
of  Paul,  is  established. — Take  an  ivory  billiard  ball  at  two 
paces  distance.  It  excites  in  us  a  certain  crude  sensation  of 
the  retina  and  the  muscles  of  the  eye,  which  calls  up  the  im- 
age of  the  muscular  sensations  of  locomotion  which  would  lead 
our  hand  two.  paces  off,  according  to  a  certain  outline  ;  the 
compound  is  a  patch  of  color  with  a  certain  shape,  and  situ- 
ated in  appearance  two  paces  from  us. — We  reach  forward  our 
hand  and  feel  the  ball ;  it  produces  in  us  a  certain  crude  sen- 
sation of  cold,  of  even  contact,  of  resistance,  which  calls  up  the 
image  of  the  tactile  and  visual  sensations  which  we  should 
have  if  we  were  to  look  at  or  touch  our  right  hand  ;  the  com- 
pound is  a  sensation  of  even  contact,  resistance,  and  cold,  ap- 
parently situated  in  our  right  hand. — Now,  whenever  we  have 
repeated  the  experiment,  each  one  of  these  two  compounds  has 
always  accompanied  the  other.  Consequently,  in  any  interval 
of  time,  however  long  and  however  divided  it  may  be,  we  can- 
not imagine  a  moment  in  which,  where  one  of  the  two  com- 
pounds is  given,  the  other  cannot  and  must  not  also  be 
given,  so  that  the  possibility  and  necessity  of  both  last  without 
discontinuity,  during  all  the  moments  of  the  interval ;  this  is 


366  THE  KNOWLEDGE  OF  MIND.  [BOOK  III. 

what  we  express  by  saying  that  there  is  in  it  something  sta- 
ble which  is  permanently  tangible,  resisting,  and  clothed  with 
color. — To  this  compound  so  constructed  are  added  the  im- 
ages of  the  distinct  visual  sensations,  which  the  ball  would  ex- 
cite in  us,  according  to  the  differences  of  light  and  distance ; 
from  all  these  connected  appearances,  is  formed  the  internal 
semblance  which  now  springs  up  in  us  in  the  presence  of  the 
ball. — Add  two  other  compounds,  the  image  of  the  sensations 
by  which  we  ascertain  the  changes  which  on  certain  condi- 
tions the  ball  undergoes,  and  the  image  of  the  sensations  by 
which  we  ascertain  the  changes  which  the  ball  on  certain  con- 
ditions excites  in  any  other  body. — Such  is  the  vast  collection 
of  intellectual  atoms  joined  one  by  one  and  group  to  group, 
of  which  all  the  groups  spring  up,  or  are  ready  to  spring  up 
within  us,  when  the  crude  visual  sensation  of  the  white  form 
or  the  crude  tactile  sensation  of  smooth  contact,  cold,  and  re- 
sistance, is  produced  in  us. 

Now  let  us  suppose  the  sensation  to  cease,  and  all  that 
subsists  of  it  to  be  the  image  with  its  appurtenances,  that  is 
to  say  a  representation  of  the  ball,  and  let  us  assume  that  a 
different  sensation  may  rise  at  the  same  moment  with  its 
special  train.  By  this  attachment  of  a  contradictory  sensa- 
tion, the  representation  of  the  ball  appears  something  internal, 
a  past  event ;  and,  in  this  manner,  it  arouses  other  analogous 
representations,  in  the  midst  of  which  it  fixes  itself  in  such  a 
way  as  to  constitute  with  them  a  line  of  internal  events  ;  this 
line  is  opposed  to  other  groups,  because  all  its  elements 
present  a  constant  character,  which,  being  continually  repeated, 
seems  persistent,  that  is  to  say,  the  particularity  of  being  a 
within,  in  opposition  to  the  without ;  and  this,  later  on,  will 
offer  to  reflection  and  language  the  temptation  to  isolate  it 
under  the  name  of  subject  and  Ego. — In  this  immense  chain, 
each  class  of  internal  events,  sensations,  perceptions,  emotions, 
each  species  of  perceptions,  of  sensations,  and  emotions  has 
its  image  associated  with  that  of  its  conditions  and  of  its 
internal  and  external  effects ;  and  this  forms  an  infinite 
number  of  new  couples,  the  two  links  of  which  draw  one 
another  into  the  light ;  so  that  we  cannot  imagine  any  pain 
without  imagining  its  condition — a  particular  nervous  lesion 


CHAP.  I.J  THE  KNOWLEDGE   OF  MIND.  367 

— and  without  imagining  its  effect — a  contraction  or  a  com- 
plaint.— Now,  by  a  necessary  suggestion,  when  an  external 
body  presents  the  conditions  and  effects  of  our  own,  the 
group  of  sensations  which  represent  it  calls  up  in  us  a  group 
of  images  analogous  to  those  by  which  we  represent  to  our- 
selves our  own  events ;  and  this  forms  a  last  compound,  the 
most  extensive  of  all,  since  it  comprises  a  body  and  a  soul, 
with  all  their  mutual  connections  and  all  the  connections 
which  join  their  events  to  the  events  of  others. — Thus,  in 
our  mind,  every  compound  is  a  couple;  the  couple  of  a  sen- 
sation and  an  image;  the  couple  of  a  sensation  and  of  a 
group,  or  many  groups  of  images ;  more  complex  couples,  in 
which  a  sensation,  combined  with  its  train  of  images,  contra- 
dicts a  representation  or  group  of  images ;  couples,  still  more 
vast,  in  which  a  sensation,  present  with  its  train  of  images, 
repulses  into  the  past  the  abbreviatory  images  of  a  consider- 
able fragment  of  our  life ;  couples,  the  most  comprehensive 
of  all,  in  which,  by  still  more  summary  abbreviations,  the 
sensation  and  images  which  represent  to  us  all  the  properties 
of  a  body  call  up  the  group  of  images  which  represent  to  us 
all  the  properties  of  a  soul.  Each  couple,  if  properly  con- 
structed, corresponds  in  our  mind  to  a  couple  among  events, 
and  each,  when  its  first  term  is  precisely  repeated  by  the 
present  sensation,  has,  as  its  second  term,  a  prevision. 

What  is  the  mechanism  of  this  final  operation,  the  most 
closely  allied  to  practice,  and  the  most  important  of  all,  since 
by  its  means  we  are  enabled  to  act  ? — We  foresee  that  the 
sun  will  rise  to-morrow,  that  it  will  describe  a  certain  curve 
in  the  sky,  that  it  will  set  at  such  a  spot,  at  such  an  hour, 
and  even,  with  the  aid  of  science,  that  in  so  many  years  it 
will  undergo,  at  a  particular  moment,  an  eclipse  of  certain 
extent.  Here,  as  in  recollection,  an  image  appears  projected 
from  the  present ;  only,  instead  of  being  projected  backwards 
on  the  line  of  time,  it  is  projected  forwards.  When,  this 
evening,  I  foresee  that  the  sun  will  rise  to-morrow,  what  I 
actually  have  in  my  mind  is  the  more  or  less  express  repre- 
sentation of  the  sun  at  daybreak,  of  a  golden  disc  rising  in 
the  eastern  sky,  of  nearly  horizontal  rays  which  first  illumin- 
ate the  tops  of  the  hills,  all  this  summed  up  in  a  word,  in  a 


368  THE  KNOWLEDGE   OF  MIND.  [BooK  III. 

reviving  shred  of  visual  sensation,  in  other  words,  in  a  present 
image.  This  image  appears  as  a  future  sensation,  and  fixes 
itself  by  its  anterior  extremity  on  to  the  posterior  extremity 
of  the  sensation  of  obscurity  which  I  have  at  present,  which  sit- 
uates it  in  a  determinate  point  of  the  line  of  the  future.  Here  is 
the  crude  fact ;  to  explain  it,  it  is  enough  to  refer  to  the  opera- 
tions of  memory. — There  are  two  sensations  which  have  never 
failed  to  succeed  one  another  in  us ;  on  the  one  hand,  the  sensa- 
tion of  an  obscurity  of  several  hours  ;  on  the  other,  that  of  a  lu- 
minous globe  rising  in  the  eastern  boundary  of  the  sky.  How- 
ever far  we  may  reascend  into  the  past,  the  first  has  never 
been  present  to  us  without  having  been  followed  by  the 
second,  nor  the  second  without  having  been  preceded  by  the 
first.  At  whatever  point  of  our  past  we  may  consider  them, 
we  always  find  them  joined  to  one  another  in  this  same  order. 
The  constant  repetition  has  created  the  tenacious  habit  which 
has  produced  the  energetic  tendency,  and  henceforward, 
when  we  represent  to  ourselves  the  couple,  the  first  term 
perforce  appears  to  us  as  anterior  to  the  second,  and  the 
second  as  posterior  to  the  first. — Now,  at  this  moment,  the 
first  is  a  present  sensation  ;  the  second,  then,  must  appear  as 
posterior  to  the  present  sensation,  that  is  to  say,  as  future. 
In  this  manner,  our  prevision  is  the  child  of  our  memory. 
When  given  a  couple  of  recollections  in  which  the  second 
term  appears  as  posterior  to  the  first,  if  the  first  is  found  to 
be  repeated  by  the  present  sensation,  the  second  cannot  fail 
to  appear  as  posterior  to  the  present  sensation,  and  to  situate 
itself  by  so  much  the  more  in  advance  and  more  distant  with 
relation  to  it,  as  there  is  a  greater  interval  between  the  two 
terms  of  the  primitive  couple. 

All  our  previsions,  and  consequently  all  our  conjectures, 
are  constructed  in  this  manner.  I  wish  to  move  my  arm, 
and  I  foresee  that  it  will  move ;  I  shake  a  bell,  and  foresee 
that  it  will  give  a  ringing  sound ;  I  light  a  fire  under  the 
boiler  of  a  locomotive,  and  foresee  that  the  steam  disengaged 
will  move  the  piston  ;  I  read  and  re-read  attentively  a  piece 
of  poetry,  and  foresee  that  I  shall  presently  be  able  to  repeat 
it  by  heart ;  I  address  a  question  to  my  neighbor,  and  foresee 
that  he  will  answer  me.  In  all  these  cases,  two  successive 


CHAP.  I.]  THE  KNOWLEDGE   OF  MIATD.  369 

links,  of  the  past,  are,  while  preserving  their  reciprocal  situa- 
tion, transported  out  of  their  primitive  position  to -be  placed, 
the  first  in  the  present,  the  second  at  some  point  of  the  future, 
because  we  have  ascertained,  or  believe  that  we  have  ascer- 
tained, a  perfect  resemblance  between  the  first  and  our  pres- 
ent state. 

Now,  in  fact,  the  majority  of  these  previsions  agree  with 
the  events  which  are  foreseen,  and,  in  ordinary  life,  our  ex- 
pectation is  scarcely  ever  mistaken.  We  do  not  perform  an 
act  without  reckoning  beforehand  on  its  effect,  and  this  effect 
scarcely  ever  fails  to  be  produced.  I  have  foreseen,  before 
performing  them,  all  the  movements  I  perform  with  my  body 
and  limbs,  and,  a.  hundred  thousand  times  to  one,  they  are 
such  as  1  have  foreseen.  I  have  foreseen,  before  experien- 
cing them,  the  sensations  of  resistance,  form,  position,  temper- 
ature, \vhich  will  be  given  me  by  the  somewhat  familiar  and 
not  too  distant  objects  which  I  perceive  by  sight,  and,  a  hun- 
dred thousand  times  to  one,  they  give  me  the  sensation  I  have 
foreseen.  I  foresee,  before  ascertaining  them,  the  changes 
which  a  particular  modification  of  a  certain  ordinary  body  will 
excite  in  some  other  ordinary  body,  and,  a  hundred  thousand 
times  to  one,  these  changes  will  take  place  exactly  as  I  have 
foreseen  them.  Drinking,  eating,  sleeping,  walking,  reading, 
writing,  speaking,  singing,  the  carriage  of  the  body,  the  exer- 
cise of  an  art,  a  profession,  a  trade,  no  one  of  these  common 
actions  is  accomplished  without  the  intervention  of  an  innu- 
merable multitude  of  necessarily  correct  expectations.  The 
intelligent  being,  animal  or  man,  supplies  its  wants,  preserves 
its  life,  improves  its  condition,  only  by  the  exact  accordance 
of  its  present  prevision  and  the  near  or  even  distant  future. — 
If  this  harmony  sometimes  fails,  it  is  on  account  of  the  ob- 
jects or  circumstances  in  question  being  such  that  anterior 
observation  has  not  furnished  sufficient  indications  respecting 
them.  But,  as  to  common  objects,  this  disagreement  is  infre- 
quent, and,  if  the  preliminary  experience  has  been  sufficient- 
ly extensive,  it  disappears  entirely. — There  are,  then,  a  prodi- 
gious multitude  of  cases  in  which  the  event  justifies  the  pre- 
vision, and,  in  all  these  cases,  the  couple  formed  by  our 
thoughts  is  the  exact  counterpart  of  the  couple  formed  by  the 
24 


TIIE  KNOWLEDGE  OF  MIND.  [BOOK  III 

facts.  Consequently,  the  mental  law  which  connects  our  two 
thoughts  is  as  general  as  the  physical  or  moral  law  which  con- 
nects the  two  facts. 

But  it  is  not  from  the  outset  that  we  recognize  it  as  gen- 
eral ;  primitively,  it  acts  within  us  without  our  distinguishing 
its  character  or  measuring  its  range.  The  child  and  the  ani- 
mal foresee  that  this  water  will  quench  their  thirst,  that  this 
fire  will  burn  them  ;  it  is  enough  for  this  purpose  that  experi- 
ence and  custom  have  coupled  in  their  minds  a  particular  sen- 
sation and  a  particular  representation  ;  in  their  present  cases, 
the  sight  of  water  invariably  excites  the  image  of  quenched 
thirst,  and  the  sight  of  fire  invariably  excites  the  image  of 
burning.  There  is  nothing  more  than  this ;  what  fills  their 
whole  mind  at  the  moment  is  a  certain  visual  perception  joined 
to  the  image  of  a  certain  future  sensation.  So  is  it  with  the  ma- 
jority of  our  ordinary  previsions  ;  the  adult  and  reflecting  man 
is  child  and  animal  with  respect  to  all  his  habitual  and  mechan- 
ical actions,  and  this  is  sufficient  for  his  conduct  and  practice. 
— But  he  is  capable  of  outstepping  this  state,  and,  in  fact,  by 
gradual  degrees,  he  does  outstep  it.  Not  only  is  the  mental 
law  within  him,  but  he  observes  that  it  is  within  him.  Not 
only  does  he  obey  it,  in  the  present  case,  but  he  ascertains 
that  it  holds  good  for  all  cases,  present,  past,  and  future.  By 
means  of  signs,  he  extracts,  denotes,  and  connects  the  two  ab- 
stract terms  of  water  and  of  extinguished  thirst,  the  two  ab- 
stract terms  of  fire  and  of  burning.  When  this  is  effected,  he 
considers,  by  aid  of  a  formula,  their  couple  in  itself,  exclud- 
ing all  the  particular  cases  in  which  they  are  met  with.  When 
subjected  to  this  operation,  the  couples  which  make  up  our 
animal  thought  assume  a  new  aspect,  and,  beneath  the  flow 
of  transient  and  complex  events,  we  perceive  the  world  of 
fixed  and  simple  laws. 


CHAP.  I.]      GENERAL  CHARACTERS  AND  GENERAL  IDEAS. 


BOOK  IV. 

THE  KNOWLEDGE  OF  GENERAL  THINGS. 


CHAPTER  I. 

GENERAL  CHARACTERS  AND  GENERAL  IDEAS. 

HITHERTO  we  have  only  considered  particular  things1,  and 
the  knowledge  we  gain  of  them ;  we  have  now  to  consider 
general  things,  and  the  ideas  we  have  of  them.  For  there 
are  general  things — I  mean  thereby  things  common  to  many 
instances  or  individuals ;  these  are  characters  or  groups  of 
characters.  Observe,  for  example,  what  is  meant  by  the  word 
water,  or  the  word  drink  ;  water  denotes  a  group  of  characters 
which  is  met  with  alike  in  a  number  of  liquids,  in  that  of  wells, 
of  rivers,  of  springs,  of  the  sea  ;  drink  denotes  a  group  of  char- 
acters which  is  met  with  alike  in  a  number  of  actions,  in  all 
those  by  which  a  man  or  an  animal  causes  a  liquid  to  flow  into 
his  mouth  and  stomach.  So  is  it  with  the  other  words  of 
the  dictionary  ;  each  of  them  denotes  a  character  or  group  of 
characters  which  is  or  may  be  present  in  many  natural  cases  or 
individuals.  Here  we  have  a  new  object  of  knowledge.  Just 
as  there  are  in  our  minds  thoughts  corresponding  to  particular 
instances  and  individuals,  so  are  there  thoughts  corresponding 
to  general  characters.  These  we  call  general  ideas.  They 
form  in  our  minds  couples,  series,  aggregates  of  various  kinds,  in 
short  a  vast  complex  edifice.  We  shall  now  examine  of  what 
elements  this  mental  edifice  is  composed,  how  it  is  constructed, 
how  its  equilibrium  is  maintained,  and  under  what  conditions 
it  corresponds  to  the  real  and  natural  edifice  of  things. 


372  THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

§  I.  GENERAL  IDEAS  WHICH  ARE  COPIES. 

I.  General  characters  play  a  great  part  in  nature.  In  the 
first  place,  strange  as  the  paradox  may  appear,  a  general  char- 
acter is  requisite  to  constitute  an  individual,  a  particular  last- 
ing thing.  Whether  it  be  a  body  or  a  mind,  this  stone  or  this 
man,  there  is  a  character  connecting  its  various  successive 
moments,  a  common  character  which  we  find  alike  in  all  of 
them.  In  the  case  of  the  stone  it  is,  at  every  moment  and 
during  the  whole  duration  of  its  existence,  the  possibility  of 
exciting  in  us  the  same  sensations  of  contact,  resistance,  and 
form,  and  of  undergoing  the  same  changes  of  position  or  struc- 
ture under  the  same  circumstances  ;  in  short,  the  incessantly 
renewed  presence  of  the  same  sensible  and  physical  characters. 
In  the  case  of  the  man,  it  is  the  constant  possession  of  the 
same  aptitudes  and  the  same  inclinations,  or,  if  the  expression 
is  preferred,  the  continuous  action  of  the  same  brain. — This 
we  have  already  seen  ;  what  lies  at  the  foundation  of  the  idea 
of  self  is  the  idea  of  a  within  in  opposition  to  a  without,  all 
our  events  having  this  common  character  of  appearing  to  us 
as  internal,  in  opposition  to  others  which  appear  to  us  as  ex- 
ternal. So  again,  what  lies  at  the  foundation  of  the  idea  of 
a  particular  body  is  the  idea  of  certain  invariably  identical  sen- 
sations, which  may  under  certain  conditions  be  obtained  at 
any  moment. — In  short,  without  pushing  the  analysis  very 
far,  we  perceive  that  existence  is  in  its  nature  fragmentary, 
perpetually  repeated,  made  up  of  an  indefinite  number  of 
successive  portions,  just  like  the  flame  of  a  candle,  which  is 
a  series  of  ethereal  vibrations,  or  the  course  of  a  stream, 
which  is  a  flow  of  continually  renewed  waters.  In  this  im- 
mense flow  of  events — the  world — series  which  are  sharply 
divided  from  surrounding  series,  and  whose  elements  are  very- 
similar  to  each  other,  form  what  we  term  particular  and  indi- 
vidual beings.  Each  of  these  beings  is  a  kind  of  distinct  vor- 
tex ;  its  continuous  repetition  resembles  permanence :  in  fact 
there  is  nothing  permanent  in  it  except  its  form,  that  is  to  say 
the  group  of  characters  common  to  all  its  moments.  But,  from 
the  vanishing  and  the  incessant  diversity  of  all  its  constituent 
events,  the  group  of  its  fixed  characters  acquires  a  capital  im- 


CHAP.  I]      GENERAL  CHARACTERS  AND  GENERAL  IDEAS.      373 

portance,  and  we  legitimately  consider  it  as  the  essential  por- 
tion of  the  individual.  » 

Let  us  now  compare  with  one  another  a  great  number  of 
individuals.  It  is  a  remarkable  fact  that,  in  spite  of  the 
separations  of  time  and  space,  we  find  in  an  indefinite  num- 
ber of  individuals,  certain  characters  which  are  always  the 
same.  Six  thousand  years  ago,  the  plants  and  animals  of 
Egypt  were  similar  to  those  of  the  present  day ;  there  are 
many  kinds  of  plants  and  animals  which  have  not  varied 
throughout  the  enormous  intervals  of  geological  periods; 
from  one  end  of  the  world  to  the  other,  at  the  present 
time  and  in  epochs  separated  from  the  present  by  myriads 
of  ages,  the  little  mollusk  whose  shell  forms  chalk  has 
had  the  same  structure  and  same  existence. — Nay  more, 
many  of  our  chemical  bodies,  hydrogen,  iron,  sodium,  and 
others,  are  met  with  in  the  sun,  thirty-five  millions  of 
leagues  from  our  earth,  and  beyond  that  again  in  stars  so 
remote  that  it  takes  several  years  for  their  light  to  reach  us, 
and  that  their  distance  escapes  all  our  measurements. — At 
this  prodigious  distance  the  stars  are,  like  the  earth,  subject 
to  gravitation :  this  is  proved  by  the  movements  of  double 
stars.  Their  light  is  subject  to  the  same  conditions  as  that 
of  the  bodies  we  burn ;  this  is  proved  by  studying  the  rays 
of  the  spectrum. — Lastly,  no  scientific  man  has  any  doubt 
that,  in  accordance  with  the  laws  of  the  conservation  of 
force,  movement  must  have  always  existed  and  must  exist 
for  ever. — And  so,  just  as  there  are  common  characters 
whose  continuous  presence  connects  together  the  various 
moments  of  the  individual,  so  are  there  common  characters 
whose  multiplied  and  repeated  presence  connects  together 
the  various  individuals  of  the  class.  These  characters  are 
the  uniform  and  fixed  portion  of  dispersed  and  successive 
existence,  and  this  alone  would  suffice  to  show  us  the 
interest  we  have  in  separating  and  seizing  them. 

But  their  importance  appears  still  more  clearly  from 
another  characteristic.  We  do  not  arrange  them  merely 
for  the  convenience  of  thought ;  they  are  not  simple  means 
of  classification,  instruments  of  technical  memory.  Not 
only  do  they  exist  in  fact,  without  us,  and  often  far  beyond 


374          THE  KNOWLEDGE  OF  GENERAL    THINGS.        [BOOK  IV- 

the  short  range  of  our  senses  and  our  conjectures,  but 
more  than  this,  they  are  effective.  Each  of  them,  by  itself 
and  by  itself  alone,  draws  on  with  it  another  which  is  its 
companion,  its  antecedent  or  its  consequent,  and  so  forms 
a  couple  which  we  term  a  Law.  Thus,  in  any  animal 
whatever,  the  presence  of  mammae  implies  that  of  vertebrae. 
In  every  plant  with  two  cotyledons,  the  arborescent  bark  is 
formed  of  concentric  layers.  In  all  the  layers  of  the 
atmosphere  which  become  chilled  below  a  certain  point,  the 
included  vapor  is  precipitated  as  dew.  Whenever  two  heavy 
bodies  are  in  the  presence  of  one  another,  they  attract  each 
other  in  the  direct  ratio  of  their  mass  and  the  inverse  ratio 
of  the  square  of  their  distance.  If  the  vapor  of  sodium  be 
burnt,  its  luminous  spectrum  presents  a  yellow  ray  at  a  de- 
termined point. — All  these  examples  show  us  that  general 
characters  are  not  only  the  most  widely  distributed  inmates, 
but  also  the  most  important  agents  of  nature  ;  not  only  have 
they  the  largest  place,  but  the  principal  part  and  most  decis- 
ive activity  in  the  field  of  being. 

We  must  now  observe  that  they  are  not  all  equally  gen- 
eral. Some  are  more  so,  others  less ;  each  of  them  is  by  so 
much  the  more  general  as  it  is  less  complex,  and  so  much  the 
less  complex  as  it  is  the  more  general. — In  fact,  let  us  begin 
by  considering  the  group  of  characters  which  persists  in  a 
particular  being,  in  some  man,  through  the  successive  mo- 
ments of  his  life.  This  group  is  a  very  extensive  one ;  we 
see  this  by  the  multitude  of  details  we  are  compelled  to  give 
when  we  attempt  to  describe  a  human  person  or  soul.  But 
on  the  other  hand,  this  group  only  corresponds  with  this 
man,  and  lasts,  like  him,  for  a  short  interval  of  time  only. — 
Pass  now  from  the  individual  to  the  race  ;  the  inverse  hap- 
pens ;  here,  no  doubt,  common  characters  are  much  more  ex- 
tended in  space,  and  last  much  longer  in  time,  since  they  are 
met  with  in  an  indefinite  number  of  contemporary  individuals, 
and  are  repeated  through  an  indefinite  number  of  successive 
generations.  But,  on  the  other  hand,  they  are  themselves 
less  in  number,  since  necessarily  the  whole  of  the  characteris- 
tics which  distinguish  each  individual  from  the  rest  have  been 
left  on  one  side,  and  since  the  general  type  obtained  by  this 


CHAI-.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.       375 

retrenchment  is  a  remnant  only. — The  same  observation  is 
made  on  passing  from  the  race  or  variety,  that  is  to  say  from 
the  Negro  or  the  Indo-European,  to  the  species,  that  is  to  say  to 
Man. — Continue  and  follow  out  the  classifications  of  Natural 
History,  from  the  species  to  the  genus,  then  to  the  family, 
to  the  order,  to  the  sub-kingdom,  and  to  the  kingdom.  At 
each  step  of  the  ladder,  the  type,  impoverished  on  the  one 
hand,  enriched  on  the  other,  loses  some  of  its  preceding 
characters,  and  acquires  new  representatives;  its  elements 
are  more  restrained,  but  its  province  is  more  extensive ; 
its  contents  decrease,  while  its  extension  increases. — For 
instance,  the  species  is  less  durable  than  the  genus.  A 
particular  species  of  animal,  that  of  the  megalosaurians,  has 
perished,  after  having  existed  during  a  geological  period,  and 
the  genus  to  which  it  belonged  still  subsists  in  other  species 
which  have  since  arisen,  or  which  have  survived ;  but  the 
characters  of  the  genus  are  but  a  fragment  of  those  of  the 
species,  and  the  genus  which  survives  in  the  modern  saurians 
presents  a  portion  only  of  the  characters  of  the  species  which 
has  disappeared. — The  rule  is  everywhere  the  same.  If  we 
pass  from  organized  and  living  matter  to  mineral  and  dead 
matter,  then  to  mechanical  matter,  we  see  the  group  of  char- 
acters common  to  various  bodies  reduce  themselves,  on  the 
one  hand,  till  they  consist  of  one  or  two  qualities  almost  ab- 
solutely simple,  and  become  applicable,  on  the  other,  till  they 
include  all  bodies  real  or  imaginable. — Thus  general  charac- 
ters arrange  themselves  in  stages,  one  above  the  other,  and  in 
proportion  as  their  presence  becomes  more  universal,  their 
contents  decrease.  At  the  lowest  point  is  the  momentary 
fact,  absolutely  singular  and  distinct,  which  forms  the  element 
of  the  rest ;  every  moment,  action,  state,  or  fact,  is  thus  a 
prodigiously  complex  datum,  differing  from  every  other,  and 
having  its  special  shade  of  character.  This  shade  of  charac- 
ter subtracted,  there  remains  a  cluster  of  characters  common 
to  a  whole  series  of  facts,  and  whose  persistence  forms  the  in- 
dividual. If  from  this  cluster  we  omit  all  personal  character- 
istics, the  remainder  forms  the  race,  that  is  to  say  a  charac- 
ter present  in  the  individual  and  in  many  others.  An  extract 
from  this  remainder  is  the  genus,  that  is  to  say  a  character 


3 ?6         THE  KNOWLEDGE   OF  GENEKAL    THINGS.        [BOOK  IV. 

present  in  many  species ;  and  so  on. — By  this  series  of  sup- 
pressions we  pass,  from  a  curtailed  remainder,  to  a  remainder 
still  more  curtailed,  and,  at  the  same  time,  from  a  general 
datum  to  a  still  more  general  datum.  At  all  these  stages,  the 
general  character  is  an  abstract  character,  and  the  more  ab- 
stract as  it  becomes  more  general,  and  the  more  general  as  it 
becomes  more  abstract. 

II.  To  these  extracts  or  remnants,  present  at  several  points 
of  time  and  space,  correspond  within  us  thoughts  of  a  dis- 
tinct kind  which  we  term  general  and  abstract  ideas. — We 
have  already  shown  in  what  these  ideas  consist.*  A  general 
and  abstract  idea  is  a  name,  nothing  but  a  name,  the  signifi- 
cant and  comprehended  name  of  a  series  of  similar  facts,  or  of 
a  class  of  similar  individuals,  usually  accompanied  by  the  sen- 
sible, though  vague,  representation  of  some  one  of  these  facts 
or  individuals.  The  analysis  is  one  of  great  delicacy,  and  we 
have  already  performed  it ;  but  in  such  a  matter  we  cannot 
accumulate  too  many  examples,  and  I  beg  the  reader  will  re- 
peat the  examination  in  his  own  case,  choosing  some  very 
striking  idea  which  he  has  recently  acquired. — Here  is  one  of 
my  own,  whose  commencement  I  clearly  recall.  Some  years 
ago  I  saw  in  England,  in  Kew  Gardens,  for  the  first  time, 
araucarias,  and  I  walked  along  the  beds  looking  at  these  strange 
plants,  with  their  rigid  bark,  and  compact,  short,  scaly  leaves, 
of  a  sombre  green,  whose  abrupt,  rough,  bristling  form  cut 
in  upon  the  fine  softly  lighted  turf  of  the  fresh  grass-plat.  If 
I  now  inquire  what  this  experience  has  left  in  me,  I  find,  first, 
the  sensible  representation  of  an  araucaria;  in  fact,  I  have 
been  able  to  describe  almost  exactly  the  form  and  color  of  the 
plant.  But  there  is  a  difference  between  this  representation 
and  the  former  sensations,  of  which  it  is  the  present  echo. 
The  internal  semblance,  from  which  I  have  just  made  my  de- 
scription, is  vague,  and  my  past  sensations  were  precise.  For, 
assuredly,  each  of  the  araucarias  I  saw,  then  excited  in  me  a 
distinct  visual  sensation ;  there  are  no  two  absolutely  similar 
plants  in  nature  ;  I  observed  perhaps  twenty  or  thirty  arau- 
carias ;  without  a  doubt  each  one  of  them  differed  from  the 


*  Part  i.  book  i.  ch.  ii. 


CHAP.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS. 

others  in  size,  in  girth,  by  the  more  or  less  obtuse  angles  of 
its  branches,  by  the  more  or  less  abrupt  jutting  out  of  its 
scales,  by  the  style  of  its  texture ;  consequently,  my  twenty 
or  thirty  visual  sensations  were  different.  But  no  one  of 
these  sensations  has  completely  survived  in  its  echo  ;  the 
twenty  or  thirty  revivals  have  blunted  one  another ;  thus  up- 
set and  agglutinated  by  their  resemblance  they  are  confound- 
ed together,  and  my  present  representation  is  their  residue 
only.  This  is  the  product,  or  rather  the  fragment,  which  is 
deposited  in  us,  when  we  have  gone  through  a  series  of  simi- 
lar facts  or  individuals.  Of  our  numerous  experiences  there 
remain  on  the  following  day  four  or  five  more  or  less  distinct 
recollections,  which,  obliterated  themselves,  leave  behind  in 
us  a  simple  colorless,  vague  representation,  into  which  enter 
as  components  various  reviving  sensations,  in  an  utterly  fee- 
ble, incomplete,  and  abortive  state. — But  this  representation 
is  not  the  general  and  abstract  idea.  It  is  but  its  accompani- 
ment, and,  if  I  may  say  so,  the  ore  from  which  it  is  extracted. 
For  the  representation,  though  badly  sketched,  is  a  sketch, 
the  sensible  sketch  of  a  distinct  individual ;  in  fact,  if 
I  make  it  persist  and  dwell  upon  it,  it  repeats  some  special 
visual  sensation ;  I  see  mentally  some  outline  which  corres- 
ponds only  to  some  particular  araucaria,  and  therefore  can- 
not correspond  to  the  whole  class ;  now  my  abstract  idea 
corresponds  to  the  whole  class ;  it  differs,  then,  from  the 
representation  of  an  individual. — Moreover,  my  abstract  idea 
is  perfectly  clear  and  determinate ;  now  that  I  possess  it,  I 
never  fail  to  recognize  an  araucaria  among  the  various  plants 
I  may  be  shown  ;  it  differs,  then,  from  the  confused  and  float- 
ing representation  I  have  of  some  particular  araucaria. 

What  is  there,  then,  within  me  so  clear  and  determinate 
corresponding  to  the  abstract  character  common  to  all  arau- 
carias,  and  corresponding  to  it  alone  ? — A  class-name,  the 
name  araucaria,  pronounced  or  mentally  understood,  that  is 
to  say  a  Significant  sound,  which  is  comprehended,  and  is,  in 
this  way,  possessed  of  two  properties.  On  the  one  hand,  as 
soon  as  it  is  perceived  or  imagined,  it  awakes  in  me  the  sen- 
sible representation,  more  or  less  express,  of  an  individual  of 
the  class  ;  this  attachment  is  exclusive  ;  it  does  not  arouse  in 


THE  KNOWLEDGE  OF  GENERAL    THINGS.      [BOOK  IV. 

me  the  representation  of  an  individual  of  another  class.  On 
the  other  hand,  as  soon  as  I  perceive  or  imagine  an  individ- 
ual of  the  class,  I  imagine  this  sound  itself,  and  am  tempted 
to  pronounce  it ;  this  attachment  again  is  exclusive  ;  the  real 
or  mental  presence  of  an  individual  of  another  class  does  not 
rouse  it  in  my  mind,  and  does  not  call  it  to  my  lips. — By  this 
double  attachment  it  becomes  incorporated  with  all  the  per- 
ceptions and  sensible  representations  I  have  of  the  individuals 
of  the  class,  and  is  incorporated  with  them  alone.  But  it  is 
not  specially  attached  to  any  one  of  them  ;  it  calls  up  all  in- 
differently ;  it  is  called  up  indifferently  by  all.  Therefore,  if 
they  call  it  up,  it  is  owing  to  what  all  have  in  common,  and 
not  owing  to  what  each  has  specially ;  therefore,  again,  it  is 
attached  to  what  all  have  in  common  and  to  that  alone. — Now 
this  something  is  precisely  the  abstract  character,  the  same 
for  all  the  individuals  of  the  class.  It  is,  then,  to  this  charac- 
ter, and  to  this  character  alone,  that  the  name,  mentally  heard 
or  pronounced,  corresponds ;  which  we  express  by  saying 
that  the  name  signifies  and  denotes  the  character.  In  this 
way  the  name  is  equivalent  to  the  sight,  experience,  or  sen- 
sible representation  which  we  do  not  and  cannot  possess  of 
the  abstract  character  present  in  all  the  similar  individuals. 
It  replaces  this  character,  and  performs  the  same  functions. 
— Thus  we  conceive  the  abstract  characters  of  things  by 
means  of  abstract  names  which  are  our  abstract  ideas,  and 
the  formation  of  our  ideas  is  nothing  more  than  the  forma- 
tion of  names,  which  are  substitutes. 

How  does  a  general  and  abstract  name  arise,  and  by  what 
mechanism  does  it  contract  this  double  exclusive  attachment 
to  our  sensible  representations  and  special  perceptions  which 
gives  it  its  signification  and  value  ? — There  is  here,  as  we 
have  shown  above,  a  single  association  of  a  certain  class.  We 
point  out  a  dog  to  a  very  little  child,  and  tell  him,  in  the  lan- 
guage of  the  nursery,  imitating  more  or  less  happily  the 
barking  of  the  animal,  "  That  is  a  bow-wow"  His  eye  follows 
the  indicating  gesture  ;  he  sees  the  dog,  hears  the  sound,  and, 
after  the  apprenticeship  of  some  repetitions,  the  two  images, 
that  of  the  dog  and  that  of  the  sound,  are,  in  accordance  with 
the  law  of  the  association  of  images,  permanently  associated 


CHAP.  I.]    GENERAL  CHARACTERS  AND  GENERAL  IDEAS.        379 

in  his  mind.  In  other  words,  when  he  next  sees  the  dog,  he 
imagines  the  sound,  and  even,  by  imitative  instinct,  makes 
the  sound,  after  some  attempts.  If  the  dog  barks,  he  laughs 
and  is  delighted,  he  has  a  double  inducement  to  utter  the 
new  and  very  striking  animal  noise  of  which  he  has  as  yet 
heard  a  human  imitation  only. — So  far  there  is  nothing  orig- 
inal or  superior ;  the  brain  of  every  mammal  is  capable  of 
similar  associations ;  a  fox,  when  he  seizes  a  rabbit  certainly 
imagines  beforehand  the  sharp  quick  cry  of  the  rabbit ;  a 
sporting  dog,  who  hears  the  cry  of  a  partridge,  certainly  im- 
agines the  visual  form  of  the  partridge  in  the  air,  and,  as  to  the 
instinctive  reproduction  of  a  sound  when  heard,  there  are  the 
well-known  cases  of  parrots  and  other  kinds  of  imitative  an- 
imals. 

But  there  is  this  peculiar  to  man,  the  sound  which  has 
become  associated  in  his  case  with  the  perception  of  some 
particular  individual  is  called  up  again,  not  only  at  the  sight 
of  absolutely  similar  individuals,  but  also  by  the  presence 
of  individuals  strikingly  different,  though  in  some  respects 
comprised  in  the  same  class.  In  other  words,  analogies  which 
do  not  strike  animals,  strike  men. — The  child  says  bow-wow, 
first  to  the  house-dog,  then,  after  a  little,  he  says  bow-wow 
to  the  terriers,  mastiffs,  and  Newfoundlands  he  sees  in  the 
street. — A  little  later,  and  he  does  what  an  animal  never  does, 
says  bow-wow  to  a  pasteboard  dog  which  barks  when  squeezed 
then  to  a  pasteboard  dog  which  does  not  bark,  but  which 
runs  on  wheels,  then  to  the  silent  and  motionless  bronze  dog 
which  ornaments  the  drawing-room,  then  to  his  little  cousin 
who  runs  about  the  room  on  all  fours,  then,  at  last,  to  a  pic- 
ture representing  a  dog. — Under  these  last  circumstances,  I 
saw  a  little  boy  two  years  old  repeat  the  word  bow-wow,  some 
forty  or  fifty  consecutive  times,  with  extraordinary  wonder, 
animation,  and  delight.  He  was  held  up  to  look  at  a  shade 
placed  over  a  light,  and  ornamented  with  black  figures  of 
dogs  which  were  strongly  illuminated.  As  the  shade  was 
turned  round,  and  each  new  figure  appeared,  he  cried  bow- 
wow with  an  air  of  triumph  ;  it  was  the  enthusiasm  of  dis- 
covery ;  and  every  day  it  was  necessary  to  repeat  it.  I  de- 
termined to  count  his  exclamations ;  one  evening,  in  less 


3 So         THE  KNOWLEDGE   OF    GENERAL    THINGS.        [BOOK  IV. 

than  three-quarters  of  an  hour,  he  cried  bow-wow  fifty-three 
times  in  succession,  and  his  curiosity  was  never  wearied. — It 
with  the  aid  of  philologists  we  observe  the  primitive  mean- 
ings of  words  in  Latin,  Greek,  and  German,  and  especially, 
in  Hebrew  and  Sanscrit,  we  find  at  their  origin  a  wholly  sim- 
ilar operation  :*  a  very  loose  analogy,  that  is  to  say  a  very 
trifling  resemblance  between  two  facts,  is  sufficient  for  the 
name  given  to  the  first  to  be  applied  to  the  second. — At  the 
present  day,  too,  our  most  important  discoveries  are  made  in 
a  similar  manner.  When  Oken,  coming  across  the  skeleton 
of  a  sheep,  conceived  the  skull  to  be  a  compound  of  flattened 
and  consolidated  vertebras  ;  when  Goethe,  observing  petal- 
loid  stamens,  conceived  all  the  organs  of  a  plant  to  be  trans- 
formed leaves  ;  when  Newton,  seeing  an  apple  fall,  conceived 
the  moon  to  be  a  heavy  body  also  tending  to  fall  to  the  earth, 
they  repeated  the  mental  operation  and  experienced  the  de- 
light of  the  little  boy  who  saw  the  dogs  on  the  lamp-shade 
and  cried  out  bow-wow. — Between  a  vertebra  and  the  skull, 
between  the  green  leaf  and  a  pistil  or  stamen,  between  the 
falling  apple  and  the  moon  travelling  through  the  sky,  be- 
tween the  living  barking  dog*and  the  little  figure  on  the  lamp- 
shade, the  difference  of  appearance  is  enormous ;  it  seems 
that  the  two  representations  differ  all  in  all.  And  yet  they 
have  a  common  characteristic  ;  thanks  to  this  common  pos- 
session, the  name  called  up  by  the  first  has  also  been  called 
up  by  the  second,  and  henceforward  corresponds  to  a  very 
general  and  very  abstract  character. — All  that  distinguishes 
man  from  the  animal,  intelligent  races  from  those  of  limited 
capacity,  comprehensive  and  delicate  from  ordinary  minds,  is 
reduced  to  this  faculty  of  seizing  more  delicate  analogies,  to 
this  contagion,  by  which  the  name  of  an  individual  attaches 
to  a  more  different  individual,  to  the  property  of  more  dis- 
similar representations  or  perceptions  to  excite  the  same 
name.  For,  the  more  rare  are  the  points  of  resemblance,  the 
more  individuals  does  the  class  contain  ;  the  more  individuals 
does  it  contain,  the  more  general  and  abstract  is  the  charac- 


*  Renan,  "  De  1'Origine   du  Langage,"  pp.  125,  136.     Max  Muller,  "  The 
Science  of  Language." 


CHAP.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.       381 

ter  to  which  the  idea,  that  is  to  say  the  name,  corresponds  ; 
the  more  general  and  abstract  is  this  character,  the  more 
place  does  it  occupy  in  nature  and  the  more  individuals  does 
it  connect. — The  discovery  of  relations  between  very  remote 
objects,  the  detection  of  very  delicate  analogies,  the  extrac- 
tion of  common  characteristics  from  very  dissimilar  objects, 
the  formation  of  very  general  ideas,  the  isolation  of  very  ab- 
stract qualities — these  expressions  are  all  equivalent,  and  all 
these  operations  are  reduced  to  the  calling  up  the  same  name 
by  perceptions  or  representations  whose  resemblances  are 
very  slight,  to  the  excitement  of  the  sign  by  an  almost  imper- 
ceptible stimulus,  to  the  mental  appearance  of  the  word  upon 
a  summons  of  the  slightest  nature, 

By  means  of  this  aptitude,  the  child  of  fifteen  months  old 
learns,  in  two  or  three  years,  the  principal  words  of  ordinary 
familiar  language. — Observe  the  profound  difference  separa- 
ting this  acquisition  and  the  parallel  acquisition  which  a  par- 
rot might  make.  The  infant  invents  and  discovers  incessantly, 
and  of  its  own  accord ;  there  is  no  period  of  life  in  which  his 
intelligence  is  so  creative.  The  names  suggested  to  him  by 
his  parents  and  the  persons  about  him,  are  but  starting  points 
for  his  innumerable  efforts ;  hence  his  joy  and  trouble. — When 
once  a  name  he  receives  is  associated  in  his  mind  with  the 
perception  of  an  individual  object,  his  mind  acts  as  in  the  pre- 
vious example ;  he  applies  the  name  to  the  more  or  less  simi- 
lar objects  which  he  recognizes  as  alike.  This  wholly  sponta- 
neous recognition  appertains  entirely  to  the  child ;  a  parrot 
does  not  apply  the  name  which  is  taught  him ;  in  a  bird's 
brain,  it  remains  isolated  ;  in  a  child's  brain,  it  becomes  asso- 
ciated to  the  presence  of  a  general  character,  which  hence- 
forth has  only  to  appear  in  order  to  call  it  up.  This  is  what 
the  child  does  with  words  transmitted  from  significant  words. 
There  is  not  even  need  on  all  occasions  for  the  words  to  be 
transmitted,  with  deliberate  intention  and  by  a  human  mouth ; 
sometimes  the  child  seizes  them  in  the  involuntary  sounds  he 
utters,  or  in  the  accidental  sounds  he  catches.  "A  member 
of  my  own  family,"  says  Mr.  Lieber,*  "  showed,  in  early  in- 


*  "  Smithsonian  Contributions  to  Knowledge,"  vol.  ii.  p.  15. 


382         THE  KNOWLEDGE   OF  GENERAL    THINGS.        [BOOK  IV. 

fancy,  a  peculiar  tendency  to  form  new  words,  partly  from 
sounds  which  the  child  caught,  as  to  woh  for  to  stop,  from  the 
interjection  woh,  used  by  waggoners  when  they  wish  to  stop 
their  horses ;  partly  from  symphenomenal  emissions  of  sounds. 
Thus,  when  the  boy  was  a  little  above  a  year  old  he  had  made 
and  established  in  the  nursery  the  word  nim  for  everything  fit 
to  eat.  I  had  watched  the  growth  of  this  word.  First,  he 
expressed  his  satisfaction  at  seeing  his  meal,  when  hungry,  by 
the  natural  humming  sound,  which  we  might  express  thus, 
hm.  Gradually,  as  his  organs  of  speech  became  more  skilful, 
and  repetition  made  the  sound  more  familiar  and  clearer, 
it  changed  into  the  more  articulate  um  and  im.  Finally,  an 
n  was  placed  before  it,  nim  being  much  easier  to  pronounce 
than  im,  when  the  mouth  has  been  closed.  But  soon  the 
growing  mind  began  to  generalize,  and  nim  came  to  signify 
everything  edible  ;  so  that  the  boy  would  add  the  words  good 
or  bad,  which  he  had  learned  in  the  meantime.  He  now 
would  say  good  nim,  bad  nim,  his  nurse  adopting  the  word 
with  him.  On  one  occasion  he  said,  fie  nim,  for  bad,  repulsive 
to  eat. — There  is  no  doubt  but  that  a  verb  to  nim,  for  to  eat, 
would  have  developed  itself,  had  not  the  ripening  mind 
adopted  the  vernacular  language,  which  was  offered  to  it  ready 
made." — The  initiative  of  the  infant  is  further  shown  by  the 
incorrect  use  it  makes  of  our  words  by  giving  them  a  meaning 
which  they  have  not  for  us,  and  which  it  invents.  The  same 
child  had  learned  the  words  Good  Boy,  which  he  always  pro- 
nounced together,  and  which  formed  one  word  for  him.  "  One 
day,  wishing  to  express  the  idea  Good  Cow,  he  said  Goodboy 

Cow Similarly  a   little   girl  said   to  a  man,  Doctor 

naughty  girl,  because  he  had  teased  her." — We  may  sum  up 
the  whole  apprenticeship  of  a  child  by  saying  that  it  receives 
words,  but  creates  their  meanings,  and  that  a  series  of  contin- 
uous rectifications  are  required  in  order  that  the  meaning  it 
attributes  to  them  may  coincide  with  the  meaning  we  attrib- 
ute to  them. 

III.  Suppose  this  process  accomplished,  and  the  infant  ar- 
rived at  the  threshold  of  adult  life.  Here  begins  a  new  se- 
ries of  re-arrangements,  additions  and  corrections,  an  indefinite 
series,  carried  on  from  generation  to  generation,  and  from 


CHAP.  I.J     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.       383 

people  to  people — I  mean  scientific  research. — It  is  here  a 
question  of  making  our  general  ideas  correspond,  no  longer 
with  the  general  ideas  of  other  people,  but  with  the  general 
characters  of  things.  As  soon  as  we  are  seized  with  this  de- 
sire, a  primary  need  declares  itself ;  there  are  blanks  in  our 
ideas ;  it  is  necessary  to  fill  these  blanks. — For  instance,  the 
notion  an  ordinary  person  has  of  the  human  body  is  very 
meagre  and  incomplete ;  he  only  knows  it  in  the  rough  ;  to 
him  it  is  a  head,  a  trunk,  a  neck,  four  limbs,  of  certain  color 
and  certain  form — that  suffices  him  for  practical  purposes. 
But  it  is  clear  that  the  characters  special  to  the  human  body 
are  infinitely  more  numerous  ;  such  a  notion  represents  some 
five  or  six  only  of  the  most  obvious  ones  ;  we  must  add  to  it 
all  those  which  prolonged  and  varied  observation  can  discover. 
— The  anatomist  comes  with  the  desire  to  see  the  details  and 
the  interior;  he  dissects,  notes,  describes,  and  draws.  The 
text-book  for  beginners  contains  a  thousand  pages,  and  I  can- 
not tell  how  many  charts  and  volumes  would  be  required  to 
hold  the  figures  and  enumeration  of  all  the  parts  which  the 
naked  eye  discovers. — When  the  eye  is  aided  by  the  micro- 
scope, this  number  is  multiplied  a  hundredfold.  Lyonnet 
did  not  find  twenty  years  too  much  to  describe  the  caterpil- 
lar found  in  willow  trees. — Beyond  our  microscope,  more  pow- 
erful instruments  would  further  increase  our  knowledge  ;  it  is 
evident  that  in  this  direction  there  is  no  limit  to  the  research. 
— So,  again,  take  an  inorganic  body,  water ;  my  idea  of  it  is 
that  of  an  inodorous,  colorless,  transparent  liquid,  fit  to  drink, 
which  may  become  ice  or  steam  ;  nothing  more  ;  this  is  all  I 
know  of  the  enormous  group  of  physical  and  chemical  char- 
acters or  properties  which  accompany  and  constitute  water. 
Physicists  and  chemists  come  with  their  balances,  their  ther- 
mometers, their  electrical  machines,  their  optical  instruments, 
their  retorts,  their  reagents,  and,  in  their  hands  the  five  or 
six  meshes  which  make  up  my  idea  become  multiplied  till 
they  form  a  vast  net.  But  this  net,  however  we  may  imag- 
ine it  enlarged,  will  never  have  as  many  meshes  as  there  are 
characters  in  the  object  to  which  it  corresponds ;  for  the  dis- 
covery of  a  new  body  will  always  be  sufficient  to  add  a  new 
character  to  the  object.  At  the  beginning  of  the  century,  the 


384  THE  KNOWLEDGE   OF  GENERAL    THINGS,       [BOOK  IV. 

discovery  of  potassium  and  sodium  showed  that,  in  contact 
with  certain  metals,  water  was  decomposed  at  the  ordinary 
temperature;  here  was  a  new  character.  If  we  had  here  the 
unknown  simple  bodies  which  the  rays  of  the  spectrum  now 
indicate  to  us  among  the  stars,  and  if  we  could  submit  water 
to  their  action,  it  would  most  undoubtedly  exhibit  unknown 
properties,  which  would  have  to  be  added  to  the  list. — Mean- 
while, with  every  object,  this  list,  fruitlessly  lengthened,  re- 
mains still  open  ;  and  the  idea  we  have  of  a  species,  a  genus, 
in  short,  of  any  list  of  general  characters,  never  comprises,  and 
can  never  comprise,  more  than  a  limited  fragment  of  their 
unlimited  chain. 

Nevertheless,  this  addition  of*  new  links  is  enough  to  in- 
troduce considerable  changes  into  our  ideas.  As  furnished  by 
common  experience,  they  were  most  frequently  too  wide  or 
too  narrow ;  scientific  experience  comes  in  to  contract  or  ex- 
tend them,  to  adjust  their  corrected  dimensions  to  the  real 
dimensions  of  objects.  —  Whilst  the  examination  is  made 
roughly  and  only  bears  on  the  outer  aspects  of  things,  we 
unite,  under  a  single  name  and  idea,  fishes  strictly  so  called 
and  the  unicorn  fish,  the  dolphin,  the  cachalot,  the  whale. 
After  a  more  minute  and  penetrating  examination,  we  find 
that  this  idea  is  too  wide;  there  is  no  type  corresponding  to 
it  in  nature  ;  the  organs  of  circulation  and  respiration,  the 
skeleton  and  limbs,  are  not  the  same  in  fishes  strictly  so  called 
and  in  the  unicorn  fish,  cachalot,  dolphin,  and  whale  ;  these 
last  are  mammals ;  they  must  be  taken  from  the  class  and 
set  apart  ;  when  this  operation  is  accomplished,  my  idea,  re- 
duced to  proper  limits,  agrees  with  a  natural  group  of  charac- 
ters actually  connected  and  always  met  with  in  conjunction, 
those  of  the  fish. — My  idea  of  the  mammal  is  correspondingly 
enlarged  ;  it  was  too  narrow  as  it  only  comprised  terrestrial 
animals  with  four  legs,  and  giving  suck ;  I  have  added  to  it 
the  cetacea,  which  swim,  and  the  cheiroptera,  which  fly ; 
henceforward,  being  enlarged  and  proportioned  to  the  exten- 
sion of  the  type,  it  is  applicable  to  all  the  species  which  pre- 
sent the  same  group  of  characters,  whatever  be  their  differ- 
ence of  external  appearance  and  habitation. 

So  it  is  in  all  the  provinces  of  nature.     As  soon  as  pro- 


CHAP.  I.]      GENERAL  CHARA  CTERS  AND  GENERAL  IDEAS.       385 

found  and  prolonged  analysis  ascertains  an  ignored  and  im- 
portant character  in  a  species  of  objects,  this  species  tends  to 
leave  its  compartment  and  to  enter  another.  It  was  neces- 
sary to  burn  the  diamond  to  know  that  it  was  composed  of 
carbon :  and  it  is  merely  within  the  last  hundred  years  that 
the  formation  of  chemistry  has  enabled  the  classification  of 
inanimate  bodies. — Thanks  to  these  processes,  we  have  been 
enabled,  in  each  department  of  nature,  to  place  beings  in 
more  and  more  nearly  natural  classes,  to  arrange  as  in  an 
army,  under  companies,  battalions,  regiments,  and  divisions, 
the  enormous  multitude  of  individuals,  all  animal  forms,  all 
vegetable  forms,  the  hundred  and  twenty  thousand  species 
of  plants,  two  hundred  and  sixty  thousand  species  of  animals, 
and,  in  the  majority  of  cases,  to  determine  the  real  and  con- 
stant type  which  constitutes  each  species,  each  genus,  each 
family-,  each  order,  each  sub-kingdom. — We  have  not  invari- 
ably succeeded  in  this  ;  many  of  our  divisions  remain  artifi- 
cial, and  are  convenient  only ;  others,  provisional  ones,  await 
further  researches  to  become  definitive.*  In  mineralogy, 
especially,  there  is  as  yet  no  real  classification. — But  for  the 
majority  of  the  species  and  genera  of  animals  and  plants,  for 
the  vegetable  families  of  Jussieu,  for  the  orders  and  three 
higher  sub-kingdoms  of  Cuvier,  the  acquired  general  idea 
corresponds  with  an  actually  general  thing,  that  is  to  say 
with  a  group  of  characters  which  involve  or  tend  to  involve 
one  other,  whatever  be  the  individuals  and  circumstances 
under  which  one  of  them  is  given. 

IV.  At  present,  in  addition  to  these  general  characters, 
there  are  others  still  more  general,  which  appertain  to  the 
elements  of  the  classified  individuals,  and  which,  spread  uni- 
versally under  various  disguisements,  are,  through  their  as- 
cendancy, the  regulators  of  the  rest. — Hence  it  follows  that 
of  all  general  ideas,  those  corresponding  to  such  characters 
are  by  far  the  most  valuable. — We  attain  these  characters, 
like  the  rest,  by  taking  a  general  type  already  known,  and  by 
gradually  removing  from  it  a  number  of  accessory  characters 


*  For  instance,  the  sub-kingdom  of  zoophytes,  the  class  of  infusoria  and  that 
of  entozoa. 

25 


386  THE  KNOWLEDGE  OF  GENERAL    THINGS.       [BOOK  IV. 

so  as  to  preserve  only  the  most  stable  and  most  universal. — The 
idea  of  the  leaf  in  botany  is  of  this  kind.*  It  is  now  known 
that  the  various  organs  of  a  plant  are  nothing  more  than 
transformed  leaves.  Developed  in  spirals  on  the  stem,  they 
are  drawn  together  at  the  summit  in  superposed  horizontal 
verticils,  whose  various  stages  are  the  various  parts  of  the 
flower.  The  impoverishment  of  the  final  vegetation  has 
drawn  them  together,  and  other  circumstances  have  consoli- 
dated and  deformed  them.  Sometimes,  one  among  them  has 
become  abortive ;  sometimes,  two  or  more  of  them  have  be- 
come monstrous.  But  the  original  type  is  manifested  by  fixed 
relations,  by  sudden  reversions,  by  a  thousand  incontestible 
characteristics ;  and  the  idea  of  the  leaf,  disengaged  from  all 
sensible  impressions,  purified,  drawn  by  energetic  abstraction 
far  away  from  common  experience,  is  nothing  more  than  the 
almost  geometrical  idea  of  a  cycle  of  vegetable  elements, 
which  preserve  their  primordial  order  under  all  imaginable 
forms  and  in  all  imaginable  functions. — And  so,  in  animals, 
through  all  the  diversities  of  structure  and  function,  we  find 
throughout  the  whole  class  of  mammalia  the  same  type  of 
skeleton,  throughout  the  whole  class  of  Crustacea,  as  through- 
out the  whole  class  of  insects,  the  same  type  of  segments, 
of  mouth,  and  limbs ;  and  this  type  is  so  tenacious  that,  in 
many  species,  we  find,  to  evidence  its  presence,  the  subsist- 
ence or  appearance  of  useless  parts  or  dispositions  ;  a  suture, 
a  set  of  teeth,  a  nail,  a  bony  excrescence,  transient  or  rudi- 
mentary organs  render  it  visible  by  presenting  its  transitory 
memorial  or  surviving  remnant. 

Other  still  more  general  characters  or  groups  of  charac- 
ters are  met  with  under  the  name  of  chemical  and  physical 
properties  of  bodies,  not  only  in  the  living,  but  also  in  the 
inorganic  world.  Here  again,  the  process  which  forms  the 
corresponding  idea  is  the  same. — Vulgar  experience  has  dis- 
covered some  property  of  a  body — for  instance,  the  power  of 
amber  to  attract  to  it  small  and  very  light  objects.  Multi- 
plied and  precise  experience  multiplies  and  renders  precise 
the  circumstances  and  instances  of  this  attraction.  By  de- 


*  Auguste  Saint-Hilaire,  "  Morphologic  vegetale,"  pp.  10,  et  seq. 


CHAP.  I.]    GENERAL  CHARACTERS  AND  GENERAL  IDEAS.      38? 

grees,  we  let  slip  these  variable  characters  to  seize  only  on 
its  fixed  characters.  We  thus  isolate  a  universal  mode  of 
action,  that  is,  electric  action,  one  determinate,  purified,  ex- 
tended idea  coincides  with  a  force  which  operates  or  may 
operate  in  all  bodies. — And  so  again,  before  the  researches 
of  the  scientific  men  of  the  Renaissance,  our  idea  of  a  heavy 
body  was  that  of  a  body  tending  downwards,  and  impressing 
on  us,  when  lifted,  a  sensation  of  muscular  effort.  In  propor- 
tion to  our  discoveries  this  idea  becomes  more  abstract. — In 
the  first  place,  it  is  not  necessary  that  such  bodies  should 
afford  a  sensation  of  resistance  to  the  hand  lifting  them  ;  for 
the  air  which  sustains  the  mercury  in  the  barometer  is  heavy. 
Further,  it  is  not  only  in  a  downward  direction  that  bodies 
fall ;  for,  the  earth  being  round,  they  fall  at  the  antipodes  in 
a  different  direction  from  what  they  do  with  us.  Thus,  all 
within  our  atmosphere  falls,  and  falls  toward  the  centre  of 
our  planet. — But,  for  a  body  to  fall,  it  is  not  necessary  that 
it  should  be  comprised  in  our  atmosphere ;  of  the  two  move- 
ments which  make  up  the  whole  movement  of  the  moon,  one 
is  a  fall  towards  us. — With  two  further  steps,  the  purifica- 
tion of  our  idea  is  accomplished.  It  is  not  only  bodies 
disposed  about  the  earth  which  tend  to  fall  to  it :  all  the 
bodies  of  our  solar  system  tend  to  fall  towards  one  another. 
It  is  not  only  the  huge  heavenly  masses  which  attract  each 
other  mutually ;  all  their  molecules,  the  most  distant  and  the 
most  nearly  approaching,  attract  each  other  mutually  accord- 
ing to  the  same  law,  in  the  direct  ratio  of  their  mass  and  the 
inverse  ratio  of  the  square  of  their  distance. — Gravity,  thus 
defined,  is  a  character  so  persistent  as  to  appear  indestructi- 
ble ;  each  body  preserves  its  own,  always  equal  and  intact, 
through  all  the  changes  of  state  we  can  make  it  undergo,  and 
in  all  the  chemical  combinations  into  which  it  can  possibly 
enter. 

Such  is  the  progress  by  which  our  general  ideas  are  formed 
and  adjusted  to  general  things.  These  ideas  pass  through  two 
states.  First  the  idea  rises  with  the  sign ;  then  it  is  gradu- 
ally rectified.  In  fact,  as  we  find  it  in  current  language,  and 
as  vulgar  experience  furnishes  it,  it  corresponds  imperfectly  to 
its  object. — On  the  one  hand,  it  is  incomplete  and  vague ;  in 


388  THE  KNOWLEDGE   OF  GENERAL    THINGS.     [Boon  IV. 

other  words,  the  general  characters  which  it  denotes  are 
neither  precise  enough  nor  numerous  enough.  By  more  at- 
tentive observation  and  more  varied  experience,  we  determine 
the  ascertained  characters,  and  add  on  to  them  a  row  of  new 
characters. — On  the  other  hand  it  is  not  sufficiently  purified 
and  abstract ;  in  other  words,  among  the  characters  it  de- 
notes, there  are  accessory  and  accidental  ones  amalgamated 
with  those  which  are  important  and  fixed.  By  extended  ex- 
perience and  multiplied  comparison,  we  expel  the  parasitical 
and  transient  characters,  so  as  to  preserve  those  only  which 
are  intrinsic  and  stable. — Our  idea  has  become  adapted  to  its 
object,  first  by  addition,  then  by  subtraction. 

§  II. — GENERAL  IDEAS  WHICH  ARE  MODELS. 

I.  Another  class  of  general  ideas  presents  other  character- 
istics and  is  formed  by  another  process.  These  are  the  ideas 
which  compose  arithmetic,  geometry,  mechanics,  and  in  gen- 
eral, all  sciences  treating,  like  mathematics,  of  the  possible 
and  not  of  the  real.  We  form  these  ideas  without  examining 
whether  there  are  in  nature  objects  which  correspond  to  them, 
and  for  this  we  construct  them. 

Let  us  follow  the  detail  of  this- construction,  and  see  with 
what  elements  we  fabricate  these  new  ideas. — The  most  sim- 
ple of  all  are  those  of  arithmetic,  which  have  numbers  for  their 
objects.  Now  we  all  know  that  every  number  is  formed  by 
unity  added  to  itself;  it  is  the  notion  of  unity,  then,  which 
we  shall  first  examine. — It  comprises  nothing  mysterious,  and 
its  origin  has  nothing  strange  in  it.  We  are  not  dealing  here 
with  the  absolute  and  metaphysical  unity  which  consists  in 
the  property  of  being  indivisible,  or  rather,  without  parts,  and 
which  would  be  possessed,  for  example,  by  one  of  Leibnitz's 
monads.  We  deal  simply  with  an  office  which  any  object 
whatever  may  fulfil,  with  the  function  it  performs,  with  the 
part  it  plays,  in  contributing  with  others  like  it  to  form  a  col- 
lection. It  is  in  this  aspect  alone  that  we  consider  it ;  there- 
fore, twenty  heaps  of  stones  by  a  roadside  are,  in  this  sense, 
twenty  units  as  much  as  twenty  monads.  The  unity  of  each 
heap  is  nothing  more  than  its  aptitude  for  entering  as  a  factor 


CHAP.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.     389 

into  the  total  of  twenty  heaps,  and  into  any  other  analogous 
total,  greater  or  smaller.  Consequently  it  is,  like  every  ap- 
titude, property,  and  capacity,  nothing  more  than  a  general 
character  of  the  object,  and  this  character  may  be  disengaged, 
extracted,  and  set  apart  by  ordinary  processes,  that  is  to  say 
by  means  of  a  name,  and,  in  general,  by  means  of  a  sign. — 
Moreover,  there  is  no  character  more  easy  to  set  apart ;  for 
all  objects  and  all  events  present  it,  since  every  object  and 
every  event  contributes  with  other  similar  ones  to  form  a  col- 
lection which  is  its  class.  The  materials,  then,  from  which  the 
notion  of  unity  may  be  extracted  exists  in  superabundance, 
and  the  first  step  of  arithmetic  may  be  made  in  all  regions. 
Let  us,  then,  observe  a  series  of  objects  or  events,  taking 
care  to  consider  in  each  of  them  its  capacity  only  to  enter  as 
a  component  in  a  collection.  For  this,  let  us  purposely  omit 
all  its  other  characters ;  after  this  retrenchment,  a  row  of 
poplars,  a  series  of  sounds,  any  other  series  or  row,  ceases  to 
be  a  row  of  poplars,  a  series  of  sounds,  a  series  or  row  of  de- 
terminate objects  or  events ;  it  is  nothing  more  than  a  se- 
quence, row  or  series  of  ones  or  units.  Now  in  this  point  of 
view,  all  ones  are  the  same  one,  and  all  series  of  ones  are  the 
same  series  ;  for  the  characters  which  distinguish  individuals 
from  one  another,  and  series  from  one  another,  having  been 
excluded,  the  individuals  can  no  longer  be  distinguished  from 
one  another,  and  the  series  can  no  longer  be  distinguished  from 
one  another.  Here,  then,  we  have  an  abstract  series  com- 
posed of  abstract  units. — To  observe  this  series  more  conve- 
niently, men  have  substituted  for  it  a  sensible  series  of  very 
manageable  objects,  sometimes  of  little  pebbles,  sometimes 
the  ten  fingers  of  the  two  hands.*  Nothing  is  easier  than  to 
raise,  successively,  one  by  one,  the  fingers  of  the  closed  hand, 
or  to  lower,  successively,  one  by  one,  the  fingers  of  the  open 
hand. — Nothing  is  easier  than  to  add  pebbles,  one  by  one,  in 
such  a  way  as  to  make  a  heap,  or  to  take  away  pebbles,  one 
ty  one,  in  such  a  way  as  to  unmake  the  heap.  And  as,  by 

*  Calculation  is  derived  from  calculus,  a  little  pebble.  The  Roman  numerals 
I,  II,  III,  V,  X,  are  rude  drawings  representing  one  or  many  fingers,  one  or  both 
hands. — Our  system  of  numeration  by  tens  was  originated  by  the  fact  of  our  hav- 
ing ten  fingers. 


3QO          THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

taking  away  or  adding  one  or  more  pebbles,  by  raising  or 
lowering  one  or  more  fingers,  we  can  visibly  alter  the  total  of 
the  collected  pebbles  or  of  the  lifted  fingers,  it  is  easy,  not 
only  to  fabricate  in  this  way  various  visible  totals,  but  also  to 
observe  with  our  eyes  how  these  totals  are  made  and  unmade.* 
We  make  them  progressively,  as  to  pebbles,  by  adding  a  peb- 
ble to  the  first  pebble  and  so  on,  as  to  the  fingers  by  raising  a 
finger  in  addition  to  the  first  finger,  and  so  on.  We  unmake 
them  progressively,  as  to  pebbles,  by  removing  a  first  pebble 
and  so  on,  as  to  the  fingers  by  lowering  a  first  finger  and  so 
on. — These  are  the  primitive  substitutes ;  each  finger  or 
pebble  visibly  replaces  an  abstract  unit :  the  different  groups 
of  visible  fingers  or  pebbles  replace  the  different  groups  of 
abstract  units,  and,  in  proportion  as  a  visible  finger  or  pebble 
is  added  to  the  group  of  visible  fingers  or  pebbles,  a  pure  unit 
is  added  to  the  group  of  pure  units. 

At  present,  in  the  place  of  these  already  convenient  sub- 
stitutes, we  substitute  other  still  more  manageable  ones,  the 
various  sounds  which  constitute  our  names  of  number.  For 
a  lifted  finger,  we  say  one,  for  two  fingers  lifted,  two,  for 
three  fingers  lifted,  three,  and  so  on  up  to  ten.  In  this  way, 
the  name  one  replaces  a  lifted  finger,  and  therefore  an  abstract 
unit.  So,  again,  each  one  of  the  following  names  replaces  a 
group  of  lifted  fingers,  and  therefore  a  group  of  abstract  units. 
So,  finally,  when  we  pass  from  a  name  of  number  to  the  fol- 
lowing name,  a  finger  is  lifted  to  add  to  the  preceding  group 
of  lifted  fingers,  an  abstract  unit  is  added  to  the  preceding 
group  of  abstract  units,  and  the  name  of  number  expressed 
replaces  the  group  of  units  which  replaced  the  preceding  one, 
together  with  an  additional  unit.  In  other  words,  each  name 
of  number  is  equivalent  to  the  group  denoted  by  the  preced- 
ing one,  with  the  addition  of  one.f — So  as  not  to  encumber 


*  See  the  very  elegant  and  very  delicate  analysis  of  this  mental  process  in 
Condillac's  "  Langue  des  Calculs." 

f  A«  to  the  primitive  meaning  of  our  nouns  of  number  see  Bopp,  "  Compara- 
tive Grammar"  (tr.  Breal)  ii.  221.  Tri  (three)  means  "  exceeding" — i.  e.,  the  two 
i,  f  :nor  numr>?r. . —  our  probably  means,  three  plus  one  ;  five,  four  plus  one  ;  ten, 
twice  five. — A  hundred  certainly  means,  ten  times  ten. — A  thousand  probably 
means,  many,  a  great  number. 


CHAP.  I.]    GENERAL  CHARACTERS  AND  GENERAL  IDEAS.     39! 

our  memory,  we  reduce  these  names  to  what  is  strictly  neces- 
sary. When  we  get  beyond  ten,  we  say  eleven,  twelve,* 
thirteen,!  and  so  on,  till  we  get  to  nineteen. — After  nineteen, 
as  the  following  number  is  equivalent  to  twice  ten,  well-con- 
structed languages  revert  to  the  word  two,  modifying  it  suit- 
ably, and  similarly  modifying  the  names  of  the  following  num- 
bers, so  as  to  make  them  express  three  times  ten,  four  times 
ten,  and  the  sequence  of  decades  up  to  ten  times  ten.§  The 
decades  thus  form  units  of  a  second  order,  capable,  like  sim- 
ple units,  of  being  counted  up  to  ten. — Arrived  here,  we  give 
their  total  the  name  of  hundred,  and  this  new  total  forms  a 
unit  of  the  third  order,  capable  in  its  turn  of  being  repeated 
up  to  ten  hundred,  or  a  thousand,  a  unit  of  the  fourth  order. 
—The  previous  operation,  repeated  on  this  new  unit,  leads  us 
up  to  ten  thousand,  thence  to  a  hundred  thousand,  thence  to 
a  million,  and  so  on,  so  that  with  eleven  names,  arranged  in  a 
certain  order,  we  can  represent  precisely  an  enormous  group, 
such  for  instance  as  the  collection  of  two  million,  three  hundred 
and  twenty-seven  thousand,  six  hundred  and  forty-eight  units. 
An  expression  like  this  is  a  very  abbreviatory  substitute  ; 
for  it  may  be  pronounced  in  less  than  a  second ;  nothing 
shorter  has  been  found  in  the  matter  of  sounds.  But,  when 
written  for  the  eyes,  it  occupies  a  line  and  a  half,  and  requires 
sixty-seven  characters ;  this  is  a  great  deal,  and,  in  this  re- 
spect, it  may  be  improved. — For  written  names,  we  substitute 
more  simple  characters,  which,  instead  of  replacing  nouns  of 
number  directly,  and  numbers  themselves  indirectly,  replace 
numbers  directly.  These  characters  are  called  ciphers ;  it  is 
arranged  that  a  cipher  placed  to  the  left  of  another  denotes 
units  of  an  immediately  higher  order,  that  is  to  say,  ten  times 
as  great ;  we  compose  a  list  of  nine  distinct  ciphers  to  rep- 
resent the  nine  first  numbers ;  we  add  to  this  list  a  zero  to 
represent  the  absence  of  unity  or  number,  and  then,  instead 
of  sixty-seven  characters,  we  need  employ  seven  only  to  rep- 
resent a  collection  of  2,327,648  units. 

*  In  Latin,  undecim,  duodecim. 

f  In  Latin,  tredecim.     In  German,  zwo'lf,  dreizehn,  derived  from  zwei,  drei. 
p  In   German,  Zwanzig.     In    Latin,  triginta,  quadraginta,  quinquaginta,  etc. 
In  old  French,  septante,  octante,  nonante. 


3Q2  THE  KNOWLEDGE   OF  GENERAL    THINGS.     [BOOK  IV. 

Thanks  to  these  abbreviatory  notations,  we  construct  a 
prodigious  quantity  of  compounds  which  are  numbers.  For 
this,  it  is  enough  to  arrange  the  ciphers  or  to  utter  the 
names,  recollecting  the  meanings  which  our  convention  has 
imposed  on  them. — Let  us  now  observe  the  characters  of 
the  idea  so  constructed.  When  we  read  and  understand  one 
of  these  groups  of  signs,  for  instance,  2,327,648,  we  do  not 
consider  whether  nature  furnishes  an  object  corresponding 
to  our  idea.  Is  there  anywhere  a  group  of  real  units  to 
which  this  collection  of  mental  units  is,  feature  for  feature, 
adapted  ?  This  is  a  question  we  set  aside  ;  we  pay  no  heed 
to  it ;  our  idea  has  been  constructed  for  its  own  sake. — And 
yet  there  is  a  possibility  of  this  mental  construction  coinciding 
with  some  real  construction.  For  to  the  elements  of  which 
my  idea  is  constructed,  there  correspond  elements  included 
in  things.  In  fact,  what  I  call  unity,  is  the  aptitude  to  enter 
into  a  collection.  Now  there  is  no  natural  individual  or  actual 
event  which  may  not  so  enter;  whether  it  be  a  body  or  a 
mind,  an  external  or  internal  modification,  as  soon  as  we 
perceive  a  fact  or  thing,  we  put  it  in  its  class,  that  is  to  'say 
with  others  similar  to  it ;  moreover,  as  soon  as  the  object  is 
conceived  by  us,  it  spontaneously  calls  up  in  us,  without  our 
desiring  it,  and  solely  by  the  law  of  association  of  ideas,  other 
more  or  less  similar  objects.  Together  they  form  a  group  of 
more  or  less  similar  data,  each  of  them  having  the  character 
of  being  a  distinct  datum  among  many  other  analogous  ones. 
In  this  manner,  and  in  this  narrow  sense,  it  is  a  unit  among 
many  other  units. — There  are,  then,  collections  of  units  in 
nature,  as  there  are  collections  of  units  in  the  mind.  In  fact, 
there  are  a  certain  number  of  planets  about  the  sun.  There 
are,  at  this  moment,  a  certain  number  of  men,  animals,  and 
plants,  living  on  the  earth.  During  this  year,  the  earth  or 
any  other  planet,  has  advanced  a  certain  number  of  kilometres 
in  its  orbit.  During  this  year,  a  certain  number  of  persons 
have  died  in  France.  Whilst  my  mind  performs  its  additions 
and  subtractions,  nature  performs  hers.  I  fabricate  in  ad- 
vance a  long  series  of  distinct  moulds,  arranged  according  to 
their  increasing  dimensions ;  nature  fabricates,  or  has  fabrica- 
ted with  her  various  clays  all  that  is  required  to  fill  them  ; 


CHAP.  I.]    GENERAL  CHARACTERS  AND  GENERAL  IDEAS,      393 

and  the  thing  contained  is  adjusted  to  what  contains  it, 
first,  because  the  mental  elements  of  the  one  were  fashioned 
upon  the  real  elements  of  the  other,  next,  because  the  arti- 
ficial structure  of  the  containing  thing  happens  to  correspond 
with  the  natural  structure  of  the  thing  contained. 

II.  This  is  the  character  common  to  all  the  ideas  we 
construct;  they  are  preliminary  outlines;  when  we  form  one 
of  them,  we  have  no  real  thing  in  view  to  which  we  attempt 
to  make  our  thought  conform  ;  and  nevertheless,  our  thought 
is  found  to  conform  to  one  or  more  real  things  as  yet  unknown, 
which,  when  known,  will  manifest  this  conformity. 

Not  that  the  adaptation  is  always  exact ;  there  are  cases 
in  which  it  is  approximate  only.  Of  this  kind  are  geometrical 
ideas.  Let  us  first  search  for  the  elements  with  which  we 
construct  them  ;  we  all  know  that  they  are  few  in  number, 
and  we  readily  see  from  what  experiences  we  extract  them. 
—Take  any  body  observed  by  the  senses,  this  stone,  this 
piece  of  wood.  It  has,  as  limit,  one  or  more  outer  parts 
enclosing  its  inner  part ;  and  these  outer  parts  by  which  it 
terminates  are  its  surfaces.  But  each  of  these  surfaces  is 
itself  terminated  by  one  or  more  limits  which  are  called  lines, 
and  each  of  these  lines  is  itself  terminated  by  two  limits  which 
are  called  points. — So  far  there  is  no  difficulty  ;  each  of  these 
limits,  surface,  line,  or  point  is  a  character  of  the  body,  a 
character  isolated  by  abstraction,  considered  apart,  and,  more- 
over, general,  that  is  to  say  common  to  many  bodies,  or 
rather,  universal,  that  is  to  say  common  to  all  bodies.  We 
detach  this  character  and  denote  it  by  means  of  symbols, 
which  are  sometimes  the  names  of  surface,  line,  and  point, 
sometimes  a  class  of  sensible  objects,  very  manageable,  and 
selected  to  take  the  place  of  all  the  rest,  the  real  surface  of  a 
black  board  or  white  paper,  the  slender  trace  left  on  the 
paper  or  board  by  a  stroke  of  ink  or  chalk,  the  little  dot  left  by 
the  momentary  touch  of  the  pen  or  chalk. — The  dot  being  very 
small  we  are  disposed  to  pay  no  attention  to  its  length  and 
breadth,  though  real ;  by  this  omission  we  involuntarily  make 
abstraction  of  them,  and  have  no  difficulty  in  treating  the 
dot  as  a  point. — The  trace  being  very  thin,  we  are  not  dis- 
posed to  trouble  ourselves  about  its  breadth,  though  real ; 


394 


THE  KNOWLEDGE   OF  GENERAL    THINGS.      BOOK  IV. 


by  this  omission  we  cut  it  away,  and  come,  without  difficulty, 
to  consider  the  stroke  as  a  line. — The  board  and  the  paper 
being  very  flat,  and  level  to  the  eye  and  hand,  we  experience 
no  sensation  to  remind  us  of  their  thickness ;  by  this  omission 
we  suppress  it,  and  are  led  to  consider  the  board  and  paper 
as  true  surfaces. — In  this  way  the  board,  the  narrow  stroke, 
the  little  spot  of  chalk,  become  convenient  substitutes.  They 
are  sensible  and  special  things,  but  they  replace  wholly 
abstract  and  general  limits,  in  the  same  way  as,  just  now,  in 
arithmetic,  pebbles  and  fingers  replaced  pure  units. 

To  these  elements  so  represented,  add  another  movement ; 
it  is  also  met  with  in  the  majority  of  bodies  we  perceive ;  we 
are,  then,  capable  of  detaching  it  from  them.  When  once 
these  data  are  extracted,  it  is  sufficient  to  combine  them  in 
different  ways  to  obtain  all  geometrical  compounds.  In  ad- 
dition to  this,  by  a  still  further  reduction,  we  find  that  the 
point  and  movement  are  sufficient  elements  for  the  reconstruc- 
tion of  the  two  other  kinds  of  limits  which  we  have  termed 
the  line  and  surface,  and  further,  of  the  solid  body,  from 
which  we  have  drawn,  with  the  ideas  of  surface  and  line,  those 
of  point  and  movement. — In  fact,  imagine  a  point,  that  is  to 
say  the  limit  of  a  line,  and  assume  that  it  moves ;  the  con- 
tinuous series  of  positions  it  occupies  forms  a  line.  Assume 
this  line  to  move ;  the  continuous  series  of  the  positions  it 
occupies  forms  a  surface.  Assume  this  surface  to  move ;  the 
continuous  series  of  the  positions  it  occupies  forms  a  solid 
body,  at  least,  in  a  geometrical  point  of  view.  And  the  substi- 
tutes we  have  adopted  for  the  point,  line,  and  surface,  render 
this  construction  sensible  to  us.  By  prolonging  this  little  dot 
of  chalk,  we  see  a  slender  trace  produced.  By  causing  this 
whole  trace  to  move  in  a  mass,  we  see  a  greater  or  less  surface 
produced.  By  mentally  causing  the  surface  of  the  board  to 
recede,  we  see  the  whole  solid  board  produced. — From  this 
general  construction,  let  us  pass  to  special  ones.  Let  there 
be  two  points ;  if  the  first  moves  towards  the  second,  and 
towards  the  second  only,  the  line  it  describes  is  straight. — If, 
during  an  appreciable  fragment  of  its  movement,  it  moves 
towards  the  second  point,  and  then,  during  other  equally  ap- 
preciable fractions,  towards  a  third,  a  fourth,  etc.,  the  line  it 


CHAP.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.       395 

describes  is  broken,  or  composed  of  distinct  straight  lines. — If 
at  each  instant  of  its  movement  it  moves  towards  a  different 
point,  the  line  it  describes  is  curved.  Such  are  the  different 
species  of  lines. — Next,  if  two  straight  lines  start  from  the 
same  point,  and  move,  each  towards  a  different  point,  they  di- 
verge from  one  another,  and  this  greater  or  less  divergence  is 
called  an  angle.  If  the  two  angles  which  the  second  line 
makes  to  left  and  right  with  the  first  are  equal,  they  are  called 
right  angles,  and  we  say  that  the  second  line  is  perpendicular 
to  the  first.  Such  are  angles. — With  straight  lines  cutting 
each  other  in  pairs,  and  forming  certain  angles,  we  construct 
all  triangles,  all  quadrilaterals,  and  generally,  all  polygons. — 
If  we  submit  a  curve  to  the  condition  of  having  all  its  points 
at  an  equal  distance  from  some  other  anterior  point,  we  have 
circumference. — "  The  plane  surface,  or  plane,  is  generated  by 
a  straight  line  perpendicular  to  another,  and  turning  about  it 
while  always  passing  through  some  one  point  in  it."*  With 
planes  terminated  by  certain  polygons  and  forming  certain 
angles  by  their  mutual  inclination,  we  construct  all  poiyhedra. 
— By  the  revolution  of  the  semicircle  about  its  diameter,  of 
the  rectangle  about  one  of  its  sides,  of  the  right  angled  tri- 
angle about  one  of  the  sides  containing  the  right  angle,  we 
form  the  sphere,  the  cylinder,  the  cone ;  by  sections  of  the 
cone,  we  form  the  ellipse,  parabola,  and  hyperbola ;  by  vari- 
ous combinations  of  the  primitive  elements,  and  of  these  first 
compounds,  we  form  all  possible  species  of  lines,  surfaces,  and 
solids,  sometimes  so  complex  that  imagination  cannot  form 
them,  and  that,  if  nature  or  art  were  to  furnish  instances  of 
them,  the  most  attentive  eye  could  not  contrive  precisely  to 
distinguish  all  their  characters. 

Are  there  in  nature  physical  constructions  conforming  to 
these  mental  constructions  ? — And  first,  are  there  in  nature 
surfaces,  lines  and  points  ?  Yes,  certainly,  at  least  as  far  as 
our  senses  are  concerned  ;  for,  to  our  senses,  a  body  has  sur- 
faces which  are  the  limits  in  which  it  appears  to  be  contained, 
a  surface  has  its  lines  which  are  the  limits  by  which  it  seems 
circumscribed,  a  line  has  its  points  which  are  the  limits  by 


*  Duhamel,  "  De  la  Methode  dans  les  sciences  de  raisonnement,"  2iue  partie,  12. 


396        THE  KNOWLEDGE   OF   GENERAL    THINGS.        [BOOK  IV. 

which  it  seems  to  be  terminated,  or  by  which  we  may  inter- 
rupt it. — Are  there  in  nature  surfaces,  lines,  and  points  which 
move  ?  Yes,  since  bodies  move  and  their  limits  accompany 
them  in  their  movement. — Next,  are  there  in  nature  points, 
lines,  and  surfaces,  which,  in  their  motions  and  combinations, 
rigorously  conform  to  the  conditions  enunciated  in  our  con- 
structions ?  In  other  words,  are  there  perfect  straight  lines, 
right  angles,  squares,  circles,  planes,  polyhedra,  round  bodies  ? 
— As  far  as  we  can  judge,  nature  does  not  furnish  us  with 
such.  When  we  arm  our  eye  with  a  powerful  microscope,  we 
find  inflections  in  what  seem  the  straightest  lines,  roughness 
in  the  smoothest  planes,  irregularities  'in  the  most  regular 
forms.  A  cannon-ball  appears  to  advance  in  a  straight  line  ; 
theory  shows  us  that  it  begins  to  fall  the  moment  it  leaves  the 
cannon.  The  planets  seem  to  describe  an  ellipse  ;  observa- 
tion and  the  calculations  of  their  perturbations  prove  that  this 
ellipse  is  not  exact. — In  short,  when  we  compare  the  work  of 
nature  and  the  work  of  the  mind,  we  prove  that  their  conform- 
ity is  not  entire  ;  the  first  approximates  to  the  second  ;  that 
is  all.  Usually,  this  coincidence  is  remote  enough,  but,  even 
in  the  most  favorable  instances,  it  fails  in  some  point ;  we 
might  say  that  the  real  substance  attempts  to  mould  itself  on 
the  mental  form,  but  that  the  imperfection  of  its  material  hin- 
ders it  from  copying  rigorously  the  prescribed  shape. 

There  is  a  reason  for  this  impotence  ;  and,  if  we  take 
cases  whose  theory  is  constructed,  we  are  able  to  explain  it. 
The  cannon-ball  would  advance  continuously  in  a  straight 
line,  if  gravity  did  not  cause  it  to  descend  towards  the  ground. 
The  planet  would  describe  a  perfect  ellipse,  if  the  variable 
proximity  of  the  other  planetary  bodies  did  not  intervene  to 
alter  the  regularity  of  its  curve.  If  the  ball  deviates  from  its 
straight  line  and  the  planet  from  its  ellipse,  it  is  through 
other  perturbing  directions  being  added  to  the  simple  direc- 
tion followed  by  the  ball,  to  the  two  simple  directions  accord- 
ing to  which  the  planet  travels.  Consequently,  if  the  real  con- 
struction is  but  approximately  adjusted  to  the  mental  con- 
struction, it  is  owing  to  the  first  being  more  complex  and  the 
second  simpler.  Disencumbered  of  its  accessory  elements, 
and  reduced  to  its  principal  elements,  the  first  would  pre- 


CHAP.  I.]    GENERAL  CHARACTERS  AND  GENERAL  IDEAS.        30,7 

cisely  copy  the  second  ;  and  in  fact,  it  does  approximate  to 
it  in  proportion  as  its  ulterior  or  accessory  elements  become 
feeble,  and  leave  greater  ascendancy  to  its  primitive  or  prin- 
cipal element. — Thus,  in  geometry,  as  just  now  in  arithmetic, 
our  preliminary  outlines  have  a  function  and  a  value.  Though 
constructed  on  their  own  accounts,  they  have  a  relation  with 
things.  In  a  certain  sense  they  are  exact,  and,  with  a  com- 
plementary operation,  they  may  become  so.  The  divergence 
we  observe  between  them  and  the  facts  may  disappear,  and 
does  in  fact  disappear  in  two  ways. — We  have  seen  it  disap- 
pear by  an  abstraction,  that  is  to  say  by  the  mental  omission 
of  certain  elements  of  the  facts  ;  in  this  way,  the  reduced 
facts  are  adjusted  to  the  outlines. — It  may  also  disappear  by 
an  inverse  process,  that  is  to  say  by  the  introduction  into  the 
outlines  of  the  elements  omitted  in  their  preliminary  con- 
struction ;  to  the  consideration  of  the  principal  or  primitive 
directions,  we  add  those  of  the  perturbing  directions,  whether 
ulterior  or  accessory,  and,  in  this  way,  the  completed  outlines 
will  be  adjusted  to  the  facts. 

III.  Other  elements,  fashioned  like  the  preceding  ones  on 
the  general  characters  of  natural  objects,  combine  with  the 
preceding  ones  to  form  new  outlines.  We  may  consider 
movement,  not  only  as  having  the  effect  of  describing  a  line, 
but  in  itself.  Daily,  beneath  our  eyes,  a  prodigious  quantity 
of  bodies  are  at  rest  or  in  motion,  so  that  in  this  point  of 
view  experience  furnishes  us  with  all  the  materials  necessary 
to  enable  us  to  isolate  the  two  elementary  ideas  of  rest  and 
motion. 

Take  a  body  in  motion ;  it  passes  from  one  point  to  an- 
other while  describing  a  line ;  we  have  many  occasions  of  ob- 
serving that,  according  to  circumstances,  this  same  line  is  de- 
scribed in  more  or  less  time,  and  we  thence  draw  a  new  ele- 
mentary idea,  that  of  velocity. — Take  a  body  passing  from 
rest  to  motion ;  in  the  majority  of  cases,  we  discover  that 
something  has  been  altered  in  it  or  in  its  surroundings,  and 
after  a  certain  number  of  experiences  we  ascertain,  or  believe 
that  we  ascertain,  that  this  internal  or  external  alteration  is 
always  followed  by  the  movement  of  the  body.  Whatever 
be  this  condition  of  motion,  the  import  of  another  body,  the 


398  THE  KNOWLEDGE  OF  GENERAL    THINGS.      [BOOK  IV. 

attraction  of  a  magnet,  electric  repulsion,  whether  it  appear 
to  reside  in  the  moved  body  or  in  another,  is  of  no  impor- 
tance ;  we  call  it  force,  without  forming  any  previous  conclu- 
sion as  to  its  nature,  and  we  mean  nothing  more  by  this  name 
than  a  condition  whose  presence  is  sufficient  to  excite  the 
motion,  a  condition  which  is  met  with  in  an  infinite  number 
of  various  circumstances,  and  which,  when  detached  and  iso- 
lated by  a  mental  fiction,  thus  becomes  wholly  general  and 
abstract.  In  this  state  of  purity,  it  is  defined  only  by  its  re- 
lation with  the  movement  it  excites.  Therefore,  if  in  the 
movement  it  excites  we  find  a  character  susceptible  of  magni- 
tude, the  force  will  be  susceptible  of  magnitude ;  now,  we 
have  just  seen  that  this  character  is  velocity.  In  this  man- 
ner, we  speak  of  a  force  as  double  or  triple  another ;  and  we 
thereby  mean  nothing  more  than  a  condition  whose  pres- 
ence is  enough  to  excite  in  the  same  body,  surrounded  by 
the  same  circumstances,  a  movement,  twice,  thrice,  four,  etc., 
times  as  rapid  as  the  first. 

When  this  is  settled,  we  can  take  a  step  in  advance. 
Among  the  bodies  we  examine,  there  are  some  which  appear 
to  us  homogeneous,  that  is  to  say  composed  of  particles  all 
of  which  are  perfectly  similar,  except  in  the  difference  of  their 
position  in  the  body ;  such,  for  instance,  is  a  measure  of  pure 
water,  a  piece  of  refined  gold.  From  this  indication  of  ex- 
perience, we  have  no  difficulty  in  conceiving  an  absolutely 
homogeneous  movable  body,  analogous  to  a  pure  geometrical 
solid,  divisible  therefore  into  two  halves,  each  composed  of 
the  same  number  of  exactly  similar  particles.  Now,  take  a 
force  which  impresses  a  certain  velocity  on  the  block  formed 
by  the  half  of  these  particles  ;  as,  by  definition,  these  two 
halves  are  absolutely  similar  and  may  be  substituted  without 
inconvenience  for  one  another,  it  will  require  a  force  abso- 
lutely similar  and  capable  of  being  substituted  without  incon- 
venience for  the  other,  that  is  to  say,  in  short,  an  equal  force, 
to  impress  the  same  velocity  on  the  block  formed  by  the 
other  half,  consequently  two  forces,  each  equal  to  the  first, 
that  is  to  say  a  double  force,  to  impress  the  same  velocity 
on  the  block  formed  by  the  two  halves.  Thus  arises  our  last 
elementary  notion,  that  of  mass,  which  is  found  to  be  a  quan- 


CHAP.  I.]     GENERAL  CHARACTERS  AND  GENERAL  IDEAS.       30,9 

tity  like  velocity,  and  henceforward,  we  measure  force  in  two 
ways,  either  by  the  magnitude  of  the  mass  on  which  it  im- 
presses a  certain  velocity,  or  by  the  velocity  which  it  im- 
presses on  a  certain  mass.  With  these  elements,  denoted  by 
means  of  lines,  ciphers,  and  words,  we  are  able  to  construct 
an  infinite  number  of  different  mental  compounds,  to  conceive, 
first,  a  movable  body  at  rest,  or  to  which  no  force  is  applied, 
then,  a  movable  body  at  rest  to  which  a  force  is  applied,  then, 
by  a  further  complication,  to  imagine  a  movable  body  to 
which  are  applied  two  or  more  equal  or  unequal  forces,  which 
impel  it  in  the  same  line,  in  the  same  or  in  contrary  direc- 
tions, or  which  impel  it  in  different  lines,  etc.  By  this  opera- 
tion, the  science  of  mechanics  acquires  similar  outlines  to 
those  of  geometry,  and  the  facts  conform  to  the  outlines  in 
the  first  case  in  the  same  manner  and  in  the  same  degree  as 
in  the  second. 

One  of  the  most  simple  of  these  intellectual  combina- 
tions is  that  of  a  movable  body  at  rest  and  remaining  at  rest 
for  an  indefinite  period  ;  for,  in  this  case,  there  is  no  idea  of 
a  new  state  introduced. — Another,  which  is  fellow  to  it,  and 
almost  equally  simple,  is  that  of  a  body  in  motion  which 
moves  on  in  a  straight  line  with  uniform  velocity,  and  that  in- 
definitely; for,  to  form  this  conception,  requires  a  minimum 
of  mental  elements.  In  the  first  place,  there  is  no  simpler 
line  than  the  straight  line,  since,  when  the  starting  point  is 
given,  all  required  to  determine  it  is  a  single  second  point, 
whilst  for  every  other  line,  broken  or  curved,  many  or  an  in- 
finite number  of  such  points  are  required.  Secondly,  it  is 
more  simple  for  velocity  once  given  to  subsist  invariably  with 
the  same  magnitude  ;  for  in  this  way,  no  new  magnitude  is 
introduced.  Lastly,  it  is  more  simple  for  the  movement, 
once  given,, to  subsist  indefinitely;  for  in  this  way,  no  new 
state  is  introduced. 

Now  it  is  an  admirable  thing  that  the  bodies  of  nature, 
however  different  they  may  be,  however  different  may  be  the 
real  forces  by  which  they  are  set  in  motion,  or  the  real  circum- 
stances in  which  they  happen  to  be  at  rest,  all  tend  to  con- 
form to  this  double  conception.  We  assure  ourselves  of  this 
y  experience ;  real  matter  is  inert,  and  indifferent  to  rest  or 


400  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

motion.  In  order  for  a  body  at  rest  to  move,  the  interven- 
tion of  a  force  is  required ;  if  this  intervention  is  wanting,  it 
remains  indefinitely  at  rest,  and  its  tendency  to  persist  in  its 
state  is  so  thoroughly  inherent  to  all  its  particles,  that,  accord- 
ing to  the  magnitude  of  its  mass,  it  requires  a  force  of  corres- 
ponding magnitude  to  impress  on  it  the  same  velocity. — On 
the  other  hand,  in  order  that  a  body  in  motion  may  stop,  or 
change  its  velocity,  or  deviate  from  a  straight  line,  there  is 
also  required  the  intervention  of  another  force.  This  stone 
which  I  cast  in  the  air,  this  ball  driven  from  the  cannon  by 
the  explosion  of  powder,  would  continue  their  route  indefi- 
nitely, the  one  towards  the  stars,  the  other  along  a  tangent  to 
the  earth,  in  a  straight  line,  with  the  initial  velocity,  if  gravity 
and  the  resistance  of  the  air  did  not  intervene  to  bend  the 
straight  line,  to  diminish  the  velocity,  and  finally,  to  arrest 
the  movement.  As  far  as  we  can  judge  by  observation,  there 
is  no  particle  of  matter,  at  rest  or  in  motion,  which,  taken  by 
itself  and  with  the  abstraction  of  all  perturbing  solicitations, 
does  not  conform  itself  to  this  conception. 

Let  us  now  introduce  a  new  condition,  the  simplest  we 
can,  into  our  mental  compound  ;  let  us  suppose  the  initial 
force,  instead  of  acting  at  the  first  instant  only,  to  continue 
to  act  during  the  whole  duration  of  the  movement,  and 
consequently  the  velocity  of  the  movement  to  increase  uni- 
formly. By  a  coincidence  almost  as  beautiful  as  the  preced- 
ing one,  we  find  that  this  kind  of  motion  is  that  of  all  falling 
bodies.* — Lastly,  let  us  imagine  a  body,  subject  to  this  kind 
of  motion,  and  to  uniform  rectilinear  motion  besides.  The 
coincidence  is  no  less  surprising ;  to  our  intellectual  construc- 
tion corresponds  a  real  movement,  similarly  composed  in  all 


*  "  '  When  a  stone  falls,'  says  Galileo, '  if  we  consider  the  matter  attentively, 
we  shall  find  that  there  is  no  addition,  no  increase,  of  the  velocity  more  simple 
than  that  which  is  always  added  in  the  same  manner,'  that  is,  when  equal  addi- 
tions take  place  in  equal  times.  From  this  law,  thus  assumed,  he  deduced  that 
the  spaces  described  from  the  beginning  of  the  motion  must  be  as  the  squares  of 
the  times  ;  and  again,  assuming  that  the  laws  of  descent  for  balls  rolling  down  in- 
clined planes,  must  be  the  same  as  for  bodies  falling  freely,  he  verified  this  con- 
clusion by  experiment." — Whewell's  "  History  of  the  Inductive  Sciences,"  ii.  30, 
citing  Galileo.  '  Dial.  Sc.'  iv.  p.  91. 


CHAP.  I.]      GENERAL  CHARACTERS  AND  GENERAL  IDEAS.     401 

respects,  with  respect  to  the  curve  traced,  with  respect  to  the 
alternately  increasing  and  decreasing  velocities,  that  of  the 
planets  about  the  sun.  Thus  it  is  that  the  mathematician 
prepares  beforehand  moulds  which  the  physicist  will  subse- 
quently proceed  to  fill. — There  are  three  conditions  requisite 
for  these  moulds  to  have  a  chance  of  agreeing  with  things. 
It  is  first  necessary  for  the  mental  elements  with  which  they 
are  fabricated  to  be  traced  in  exact  accordance  with  the  ele- 
ments of  real  things;  for  then  the  elements  of  our  mould 
will  be  found  in  nature. — It  is  then  necessary  for  them  to  be 
very  general,  and,  if  possible,  universal,  for  the  more  general 
they  are,  the  more  considerable  will  be  the  number  of  indi- 
viduals or  instances  in  which  they  will  be  found,  and  if  uni- 
versal, they  will  be  found  in  all. — Lastly,  it  is  necessary  for 
the  combinations  we  give  them  to  be  as  simple  as  possible ; 
for  there  is  the  more  chance  of  our  finding  them  in  nature, 
since  a  minimum  of  elements  and  conditions  is  then  sufficient 
for  their  production. 

IV.  It  will  be  understood  that  this  process  may  be  applied 
to  all  classes  of  objects,  since,  in  all  classes  of  objects,  we  meet 
and  isolate  general  characters  capable  of  being  combined  with 
one  another.  In  fact,  we  suppose  perfect  solids,  that  is  to  say 
bodies  absolutely  rigid,  and  such  that,  all  their  parts  being  in- 
dissolubly  connected,  one  particle  cannot  be  displaced  without 
displacing  all  the  rest,  in  such  a  way  that  the  reciprocal  posi- 
tion of  their  particles  is  never  altered  in  any  way.  And  so,  we 
assume  the  existence  of  perfect  or  absolutely  fluid  liquids, 
such  that  no  one  of  their  particles  has  the  least  adherence  to 
the  adjacent  ones,  and  that  all  can  move  with  perfect  freedom 
about  one  another.  So  finally,  we  conceive  water  or  oxygen 
as  absolutely  pure,  platina  or  lead  as  free  from  all  alloy,  with- 
out being  sure  that  nature  ever  furnishes,  or  art  has  ever  ob- 
tained, objects  such  as  we  conceive. — Among  mental  types  so 
constructed,  there  are  some  which  are  more  particularly  inter- 
esting to  us ;  they  are  those  to  which  we  desire  that  things 
should  conform,  and  in  this  case  the  need  of  conformity  be- 
comes for  us  a  spring  of  action.  We  construct  the  Useful, 
the  Beautiful,  and  the  Good,  and  we  so  act  as  to  approximate 
things,  as  far  as  possible,  to  these  constructions. — For  instance, 
26 


402  THE  KNO  WLEDGE  OF  GENERAL    THINGS.     [BOOK  IV. 

when  we  find  rough  unhewn  scattered  stones,  we  imagine  them 
hewn,  transported,  and  piled  up,  in  the  spot  in  which  we  wish 
to  live,  and,  in  conformity  with  the  idea  of  the  wall  so  con- 
structed, we  actually  construct  the  real  wall  which  is  to  shel- 
ter us  from  the  weather. — We  survey  the  men  who  live  around 
us,  we  are  struck  with  a  certain  general  form  appropriate  to 
them ;  we  observe,  sometimes  in  one,  and  sometimes  in  ano- 
ther, higher  degrees  of  the  external  signs  of  some  quality  or 
disposition  beneficial  to  the  individual  or  the  race,  agility, 
vigor,  health,  sagacity,  or  energy  ;*  we  gradually  collect  these 
different  signs ;  we  take  pleasure  in  contemplating  a  human 
form  in  which  the  characters  we  consider  most  important  and 
most  valuable  are  manifested  by  a  deeper  and  more  universal 
print,  and  if  an  artist  be  found  in  whom  this  group  of  conceived 
conditions  results  in  an  express  image,  a  sensible  representa- 
tion, an  internal  half-sight,  he  takes  a  block  of  marble  and 
hews  out  the  ideal  form  which  Nature  has  not  been  able  to 
display  to  us. — Finally,  when  we  survey  the  different  motives 
which  impel  men  to  wiH,  we  observe  that  the  individual  acts 
most  frequently  with  a  view  to  his  personal  benefit,  that  is  to 
say  through  interest,  often  with  a  view  to  the  benefit  of 
another  person  whom  he  loves,  that  is  to  say,  through  sympa- 
thy, very  rarely  with  a  view  to  the  general  good,  with  complete 
abstraction  of  his"  interests  or  of  his  sympathies,  with  no  more 
regard  to  himself  or  his  friends  than  for  any  other  individual, 
without  any  other  intention  than  that  of  being  useful  to  the 
community  present  or  future,  of  all  sentient  and  intelligent 
beings.  We  separate  this  last  motive,  we  desire  that  it  should 
have  an  ascendancy  in  all  human  deliberation,  we  praise  it 
loudly,  we  inculcate  it  on  others,  we  sometimes  strive  to  give 
it  the  empire  over  ourselves.  We  have  thus  constructed  the 
idea  of  a  certain  moral  character,  and,  in  fact,  on  occasion,  at 
a  considerable  distance,  we  adapt  our  actual  character  to  this 
model. — Thus  arise  works  of  industry,  art,  and  virtue,  with 
the  object  of  filling  or  diminishing  the  interval  which  separates 
our  conceptions  from  things. 


*  I  have  worked  out  this  analysis  in  detail  in  "  La  Philosophic  de  1'Art,"  and 
in  "  L'Ideal  dans  1'Art." 


CHAP.  II.]  GENERAL  JUDGMENTS.  403 


CHAPTER  II. 

THE   COUPLES   OF   GENERAL  CHARACTERS  AND   GENERAL 
PROPOSITIONS. 

I.  HITHERTO,  in  general  ideas,  we  have  studied  only  the 
general  ideas  themselves  and  the  manner  in  which  they  are 
formed,  sometimes  by  extraction,  sometimes  by  construction, 
sometimes   when,  after   detecting   a   common   character   in 
many  similar  facts  or  individuals,  we  have  conceived  it  apart 
by  means  of  a  sign,  and  have,  by  a  series  of  additions  and 
rectifications,  caused  the  comprehension  and  extension  of 
our  idea  to  coincide  with  the  comprehension  and  extension 
of  the  character  it  denotes  ;  sometimes  when,  after   distin- 
guishing and  conceiving  apart  certain  very   simple  general 
characters,  we  have  combined  ideas  thus  acquired  so  as  to 
form   of  them   mental   compounds,   which   are   preliminary 
moulds  to  which  the  real  compounds  have  a  possibility  of 
being  found  to  conform,  or  preliminary  models  to  which  we 
desire  to  make  the  real  compounds  conform. — A  second  in- 
vestigation remains  to  be  effected.     In  nature,  general  charac- 
ters are  not  detached  from  one  another ;  whatever  be  the 
character  we  have  noted,  we  never  fail  to  find  it  connected 
with  some  other.     In  fact,  the  one  involves  the  other,  or  at 
least  tends  to  involve  it.     Sometimes  it  is  the  first  which  in- 
volves the  second,  sometimes  the  second  which  involves  the 
first,  sometimes  each  of  them  involves  the  other.      In  all 
these  cases,  the  two  characters  form  a  couple,  and  this  couple 
is  termed  a  law.     To  conceive  a  law,  is  to  connect  together 
two  general  ideas,  in  other  words,  to  form  a  general  judg- 
ment, in  other  words  again,  to  mentally  enounce  a  general 
proposition.     We  shall  now  examine  how  it  is  we  arrive  at 
connecting  these  ideas,  at  forming  these  judgments,  at  men- 
tally enouncing  these  propositions. 

II.  Let  us  first  consider  these  couples  or  laws  in  them- 


404  THE  KNOWLEDGE   OF  GENERAL    THINGS.     [BOOK  IV. 

selves.  Every  piece  of  iron  exposed  to  damp  becomes 
rusted.  Every  crystal  capable  of  scratching  any  other  body 
whatever  is  a  diamond,  that  is  to  say  a  crystal  of  pure  car- 
bon. All  bodies  immersed  in  a  liquid  lose  a  portion  of  their 
weight  equal  to  the  weight  of  the  liquid  they  displace.  In 
every  polygon,  the  sum  of  the  internal  angles  together  with 
four  right  angles  is  equal  to  twice  as  many  right  angles  as 
the  figure  has  sides. — Here  are  laws ;  each  of  them  consists 
in  a  couple  of  general  and  abstract  characters  which  are  con- 
nected. On  the  one  hand,  the  property  of  being  iron  and  of 
being  exposed  to  damp,  on  the  other,  the  formation  of  the 
chemical  compound  termed  rust ;  on  the  one  hand,  extreme 
hardness,  and  on  the  other,  the  property  of  being  a  crystal 
of  pure  carbon  ;  on  the  one  hand,  the  amount  of  weight  lost 
by  the  immersed  body,  and  on  the  other,  the  equal  quantity 
of  the  weight  of  the  displaced  liquid  ;  on  the  one  hand,  the 
sum  of  the  internal  angles  of  the  polygon  together  with  four 
right  angles,  on  the  other  hand,  the  equal  sum  of  twice  as 
many  right  angles  as  the  figure  has  sides :  it  is  evident  that 
all  these  data  are  general  characters,  that  is  to  say  characters 
common  to  an  indefinite  number  of  individuals  or  cases ; 
that  all  these  data  are  abstract  characters,  that  is  to  say  ex- 
tracts considered  apart ;  that  all  these  data  are  connected 
characters,  that  is  to  say  such  that,  the  first  being  given,  the 
second  is  also  given. — There  is  nothing  more  advantageous 
to  the  human  mind  than  this  structure  of  things  ;  we  discern 
at  once  that  our  chief  attempt  must  be  to  discover  connec- 
tions similar  to  the  foregoing  ones ;  for  there  is  no  better 
means  of  extending  and  increasing  our  knowledge.  When 
once  the  law  is  discovered,  the  first  character  becomes  the 
indication  of  the  second ;  in  future  it  will  be  sufficient  for  us 
to  ascertain  the  presence  of  the  first ;  we  may  then,  blindfold 
and  without  inquiry,  assert  the  presence  of  the  second.  In 
fact,  at  present,  it  is  sufficient  for  us  to  know  that  this  piece 
of  metal  is  iron,  and  exposed  to  damp  from  water,  steam,  or 
fog,  to  foresee  that,  in  some  hours  or  days,  it  will  be  covered 
with  rust.  It  is  sufficient  for  us  to  collect  the  water  which 
has  run  from  the  full  vessel  and  to  weigh  it,  to  know  before- 
hand the  weight  lost  by  the  immersed  body.  It  is  sufficient 


CHAP.  II.]  GENERAL   JUDGMENTS.  405 

for  us  to  count  the  sides  of  the  polygon,  to  take  two  from 
their  number,  and  multiply  the  remainder  by  two,  to  know 
beforehand  the  number  of  right  angles  contained  by  the 
polygon.  It  is  sufficient  for  us  to  observe  that  a  given  crys- 
tal scratches  the  hardest  bodies,  to  enable  us  to  declare  that 
when  burnt  it  will  furnish  carbonic  acid. —  Owing  to  these 
established  connections,  an  anatomist  who  opens  a  human 
body,  is  able  to  describe  beforehand  the  color,  form,  struc- 
ture, and  disposition  of  the  nervous  cells  and  arterial  net- 
work which  his  microscope  will  show  in  a  particular  part  of 
a  particular  organ.  Owing  to  these  established  connections, 
an  astronomer  is  able  to  predict  the  duration,  time,  and  mag- 
nitude of  the  eclipse,  which,  a  century  hence,  will  hide  the 
sun  from  the  inhabitants  of  some  particular  country. 

These  very  valuable  connections  are  of  many  kinds. — 
Sometimes  the  two  connected  characters  are  simultaneous. 
Two  cases  then  present  themselves. — Either  the  first  charac- 
ter may  involve  by  its  presence  the  presence  of  the  second 
without  the  presence  of  the  second  involving  that  of  the  first. 
Thus,  when  the  sum  of  the  digits  of  a  number  is  divisible  by 
nine,  the  number  itself  is  divisible  by  three,  but  the  converse 
is  not  true ;  when  an  animal  has  mammae,  it  has  vertebrae, 
but  the  converse  is  not  true.     In  this  case,  the  link  joining 
the  two  characters  is  unilateral  or  simple. — Or  again,  the  first 
character  may  involve  by  its  presence  the  presence  of  the  sec- 
ond, and  the  presence  of  the  second  may  involve  in  its  turn 
the  presence  of  the  first.     Thus,  in  every  polygon,  three 
sides  are  always  accompanied  by  a  number  of  angles  equal  to 
two  right  angles,  and  conversely ;  in  every  mammal,  incisor 
teeth  invariably  accompany  a  short  digestive  tube  and  car- 
nivorous instincts,  and  conversely.    In  this  case,  the  link  join- 
ing the  two  characters  is  bilateral  and  double. — Sometimes, 
of  the  two  connected  characters,  one  termed  thfe  antecedent 
precedes,  and  one  termed  the  consequent  follows ;  the  first  is 
then  termed  the  cause  of  the  second,  and  the  second  the  effect 
of  the  first.      Then  again  two  cases  present  themselves. — 
Either  the  first  character  may  excite  by  its  presence  the  ex- 
istence of  the  second,  and  the  second,  in  its  turn,  may  re- 
quire, for  its  production,  the  preliminary  presence  of  the  first. 


4o6          THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

Thus,  every  movable  body  to  which  are  applied  two  diver- 
gent forces  of  which  one  is  continuous  will  describe  a  curve  ; 
and  a  movable  body  in  order  to  describe  a  curve  requires 
the  previous  application  of  two  divergent  forces  of  which  one 
is  continuous.  In  this  case,  the  link  joining  the  two  charac- 
ters is  bilateral  or  double. — Or  again,  the  first  may  excite  by 
its  presence  the  existence  of  the  second,  without  the  second 
requiring  for  its  production  the  previous  presence  of  the  first. 
Thus,  every  series  of  vibrations  of  certain  velocity  transmit- 
ted to  the  auditory  nerve  by  the  surrounding  medium  excites 
in  us  the  sensation  of  sound  ;  but  this  sensation  may  arise 
spontaneously  in  our  sensory  centres,  without  the  previous 
vibration  of  an  external  body  or  a  surrounding  medium.  In 
this,  which  is  the  most  usual  case,  the  link  of  the  two  charac- 
ters is  unilateral  or  simple  ;  it  is  the  most  important  case  and 
the  one  which  we  shall  examine  with  most  attention ;  we  can 
reduce  the  others  to  it,  and  we  usually  express  it  by  saying 
that  the  cause  produces  the  effect. 

III.  It  now  remains  to  be  seen  in  what  the  connection  of 
the  two  characters  consists.  Is  there  any  virtue  or  secret  rea- 
son which  is  resident  in  the  one  and  involves  or  evokes  the 
other  ?  This  question  we  reserve  ;  we  shall  discuss  it  later  on. 
At  present,  the  words  connection,  link,  implication,  excite- 
ment, requirement  are  nothing  more  than  abbreviatory  meta- 
phors. When  we  say  that  the  antecedent  gives  rise  to  the 
consequent,  we  are  not  thinking  of  the  mysterious  link  by 
which  metaphysicians  connect  cause  and  effect,  nor  of  the  in- 
timate and  incorporal  force  which  certain  philosophers  insert 
between  the  thing  producing  and  the  product.  "  The  only 
notion,"  says  Mill,  "  of  which  induction  has  need,  may  be  at- 
tained by  experience.  We  learn  by  experience  that  there  is 
in  nature  an  invariable  order  of  succession,  and  that  each  fact 
is  always  preceded  by  another  fact.  We  call  the  invariable 
antecedent,  cause,  and  the  invariable  consequent,  effect."  No 
other  foundation  underlies  these  two  words.  We  wish  sim- 
ply to  say  that,  at  every  time  and  place,  the  application  of 
heat  will  be  followed  by  the  dilatation  of  bodies,  that  at  every 
time  and  place,  the  vibration  of  the  external  body  transmitted 
by  the  surrounding  medium  to  the  healthy  auditory  nerve 


CHAP.  II.]  GENERAL   JUDGMENTS.  407 

will  be  followed  by  the  sensation  of  sound.  "  The  real  cause 
is  the  series  of  conditions — the  whole  of  the  antecedents  with- 
out which  the  effect  would  not  arrive There  is  no 

scientific  foundation  for  distinguishing  between  the  cause  of 
a  phenomenon  and  the  conditions  of  its  happening  ....  The 
distinction  drawn  between  the  patient  and  the  agent  is  purely 
verbal  ....  The  cause  is  the  sum  of  negative  and  positive 
conditions  taken  together;  the  whole  of  the  circumstances 
and  contingencies  of  every  kind,  which,  once  given,  are  inva- 
riably followed  by  the  consequence."  Philosophers  are  mis- 
taken when  they  think  that  they  discover  in  our  will  a  differ- 
ent type  of  causation,  and  assert  that  we  there  see  efficient 
force  in  act  and  exercise.  Nothing  of  the  sort  is  to  be  found 
there ;  but  there  as  elsewhere,  we  find  constant  successions 
only.  We  do  not  find  fact  invariably  engendering  fact,  but 
fact  invariably  accompanying  fact.  To  quote  Mill  again : 
"  Our  will  produces  our  bodily  actions,  as  cold  produces  ice, 
or  as  a  spark  produces  an  explosion  of  gunpowder."  There, 
as  elsewhere,  we  find  an  antecedent — the  resolution  which  is 
a  momentary  character  of  our  mind,  and,  there  as  elsewhere, 
a  consequent — the  muscular  contraction  which  is  a  moment- 
ary character  of  one  or  more  of  our  organs ;  experience  con- 
nects them  and  enables  us  to  foresee  that  the  contraction  will 
follow  the  resolution,  just  as  it  enables  us  to  foresee  that  the 
explosion  of  gunpowder  will  follow  the  contact  of  the  spark. 
— More  precisely  still  and  whatever  be  the  two  characters, 
simultaneous  or  successive,  momentary  or  permanent,  the  link 
by  which  the  first  involves,  excites,  or  supposes  the  second  as 
its  contemporary,  consequent,  or  antecedent,  is  nothing  more 
than  a  peculiarity  of  the  first  considered  alone  and  apart. 
This  means  that  the  one  possesses,  in  itself,  the  property  of 
being  accompanied,  followed,  or  preceded  by  the  other;  that 
is  all.  In  other  words,  it  is  sufficient  for  the  one  to  exist  for 
the  other  to  be  its  companion,  precursor,  or  successor.  As 
soon  as  the  one  is  given,  no  other  condition  is  required ;  the 
circumstances  may  be  of  any  kind  ;  it  does  not  matter. 
Whether  it  be  given  in  a  particular  individual  with  a  particu- 
lar group  of  other  characters,  at  a  particular  time  or  place,  is 
a  matter  of  indifference  ;  the  property  it  possesses  does  not 


408  THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

depend  on  circumstances,  nor  on  the  individual,  nor  on  the 
surrounding  group  of  other  characters,  nor  on  the  place,  nor 
on  the  time  ;  taken  apart  and  in  itself,  isolated  by  abstraction, 
extracted  from  the  various  media  in  which  we  meet  with  it, 
it  possesses  this  property.  This  is  why,  into  whatever  me- 
dium we  transfer  it,  it  preserves  this  property.  If  it  possesses 
this  property  at  every  time  and  place,  this  is  because  it  pos- 
sesses the  property  of  itself  and  by  itself  alone  ;  if  it  possesses 
this  property  without  exception,  this  is  because  it  possesses 
the  property  without  condition.  If  all  triangles  enclose  angles 
together  equal  to  two  right  angles,  it  is  because  the  abstract 
triangle  has  the  property  of  enclosing  angles  together  equal  to 
two  right  angles.  If  every  piece  of  iron  exposed  to  damp  be- 
comes rusted,  it  is  because  iron  taken  apart,  in  itself,  and  sub- 
mitted to  damp  taken  apart,  and  in  itself,  possesses  the  prop- 
erty of  becoming  rusted.  If  the  law  is  universal,  it  is  from  its 
being  abstract. — There  is  nothing  surprising  in  this  constitu- 
tion of  things.  It  is  no  more  strange  to  find  companions,  pre- 
cursors, and  successors  in  the  case  of  a  general  character  than 
in  that  of  a  particular  individual  or  a  momentary  event.  No 
doubt  in  the  infinite  dispersion  and  remediless  flow  of  being, 
these  sorts  of  characters  are  the  only  elements  which  are  ev- 
erywhere the  same  and  which  always  arise  the  same  :  but  they 
do  not  exist  outside  individuals  and  events,  as  Plato  taught, 
nor  in  a  world  other  than  our  own  ;  for  they  are  the  charac- 
ters of  the  events  and  individuals  which  compose  our  world. 
They  are,  like  individuals  and  events,  forms  of  existence,  and 
differ  only  from  individuals  and  events  by  being  more  stable 
and  more  widely  spread  forms.  For  this  reason,  we  must  ex- 
pect to  discover  that  they  too  have  accompaniments,  prece- 
dents, sequences,  peculiarities,  personal  properties,  and,  to 
succeed  in  this,  we  have  only  to  observe  them  apart. 

It  is  precisely  in  this  that  the  difficulty  lies.  For  how  are 
we  to  observe  apart  a  character  which,  being  an  extract,  is 
only  met  with  and  can  only  be  met  with  in  a  particular  case 
or  individual,  that  is  to  say  in  company  with  other  charac- 
ters? How  can  we  contrive  to  study  in  nature  iron  in  itself 
exposed  to  damp  in  general,  and  to  ascertain  that,  in  this 
state  of  abstraction,  it  has  rust  in  general  as  a  consequence  ? 


CHAP.  II.]  GENERAL  JUDGMENTS.  409 

How  can  we  contrive  to  detect  the  abstract  triangle  which  is 
neither  scalene,  nor  isosceles,  nor  right  angled,  to  measure 
its  abstract  angles  which  are  neither  equal  nor  unequal,  and 
to  prove  that,  in  this  strange  state,  their  sum  is  equal  to  two 
right  angles? — From  the  question  thus  presented,  an  answer 
follows.  When  once  the  obstacle  is  clearly  determined,  we 
are  usually  able,  if  not  to  suppress  it,  at  least  to  evade  it. 
Two  artifices  of  method  lead  us  to  our  end.  We  have  dis- 
tinguished two  kinds  of  general  characters.  The  first  are 
real,  and  the  general  ideas  which  correspond  to  them,  for 
instance,  those  of  iron,  of  damp,  and  of  rust,  being  formed  by 
extraction,  become  by  degrees  adjusted  to  them  ;  they  are  the 
object  of  the  experimental  sciences;  and  their  connections 
are  discovered  by  the  inductive  road.  The  second  are  pos- 
sible only,  and  the  general  ideas  which  correspond  to  them,  for 
instance,  those  of  the  triangle,  the  angle,  parallel  lines,  being 
formed  by  combination,  are  outlines  only,  to  which  certain 
real  things  have  a  possibility  of  being  adjusted  ;  they  are  the 
object  of  the  constructive  sciences,  and  their  connections  are 
discovered  by  the  deductive  road. — Let  us  follow  these  roads 
in  turn,  and  attempt  to  observe  the  successive  stages  of  the 
mind  in  traversing  them. 

§   I.   LAWS  CONCERNING  REAL  THINGS. 

I.  Here,  in  the  first  road,  our  starting  point  is  the  already 
explained  acquisition  of  general  ideas.  In  fact,  the  child  of 
fifteen  months  old,  who  already  repeats  and  applies  certain 
general  names,  has  but  to  associate  two  of  them  in  order  to 
form  a  general  proposition,  and  this  is  what  happens  when  an 
object  which  calls  up  in  him  a  name  also  arouses  in  him 
another  name.  He  then  attempts  his  first  lisping,  verbless 
sentences: — nice  soup,  naughty  cat,  etc.  The  mechanism  of 
this  junction  is  very  simple,  and  here  animal  thought  leads 
naturally  to  human  thought. — When  a  dog  sees  in  a  trench 
or  pit  a  flowing  inodorous,  uncolored,  clear  liquid,  this  per- 
ception, by  virtue  of  anterior  experience,  excites  in  him  by 
association  the  image  of  a  sensation  of  cold,  and  the  percep- 
tion joined  to  the  image  form  in  him  a  couple.  In  the  case 


4IQ  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

of  the  child,  owing  to  the  names  he  learns  and  understands, 
the  same  perception  further  calls  up  the  word  water ;  the 
same  image  further  calls  up  the  word  cold,  and  the  two 
words  water,  cold,  associated  by  contiguity,  form  a  second 
superadded  couple. 

Now  later  on,  when  the  child  reverts  to  and  dwells  on 
these  two  words,  he  finds  that  the  first  excites  in  him  an 
indefinite  series  of  anterior  experiences,  that  of  the  water- 
bottle,  the  well,  the  spring,  the  rain,  the  river,  and  that  in 
each  of  these  representations  the  word  cold  is  called  up  as 
well  as  the  word  water.  He  then  observes  that  they  form 
a  couple  through  all  the  procession  and  all  the  review ;  this 
he  expresses  by  saying  that  all  waters  are  cold.  Somewhat 
later  on,  he  omits  the  differences  of  the  various  representa- 
tions and  preserves  the  couple  itself  alone ;  this  he  expresses 
by  saying  that  water  is  cold.  In  this  manner,  he  enounces, 
mentally  or  aloud,  his  first  general  propositions  and  his  first 
abstract  propositions. — By  degrees,  as  he  grows  older,  he 
learns  new  words ;  he  applies  them  to  the  old  couples  of 
representations  which  former  experience  has  already  es- 
tablished in  him,  and  to  the  new  couples  of  representations 
which  incessant  experience  daily  establishes  in  him ;  thus, 
arise  new  couples  of  understood  words,  that  is  to  say,  of 
ideas. — It  is  between  eighteen  months  and  five  or  six  years 
old  that  the  greater  part  of  this  process  is  accomplished ;  it 
is  continued,  later  on  and  up  to  adult  life,  but  with  fewer 
acquisitions.  The  child  thus  forms  a  number  of  judgments 
on  the  objects  and  facts  familiar  to  him.  "Sugar  is  nice. 
Fire  burns.  A  blow  hurts.  Cats  scratch.  Cows  eat  grass. 
A  person  who  speaks  harshly  is  angry." — At  first,  when 
given  an  individual  or  event  of  a  certain  class,  he  formed 
only  one  of  these  general  judgments  respecting  it ;  soon  he 
forms  two,  three,  four,  then  ten,  twenty,  a  hundred,  and  so 
on.  Seeing  a  bounding  form,  with  which  the  name  cat  is 
associated  in  his  mind,  he  says,  first,  that  the  cat  scratches ; 
later  on,  he  will  say  that  it  mews,  that  it  climbs  on  the 
roofs,  that  it  catches  mice,  and  so  on. — It  is  the  same  with 
all  other  class  names ;  each  of  them  ends  by  calling  up  a 
considerable  number  of  general  judgments,  and  each  is  capa- 


CHAP.  II.]  GENERAL  JUDGMENTS.  4!  i 

ble  of  calling  up  an  indefinite  number  of  them.  Each  of 
them  thus,  by  its  more  or  less  ample  escort,  sums  up  our 
more  or  less  ample  experience,  and  being  the  product  of  our 
experience,  affords  its  measure. 

General  judgments  of  this  kind  and  of  this  origin  are 
sufficient  for  practice.  Children,  savages,  and  uneducated 
persons  form  few  others,  and  few  others  are  made  use  of  in 
ordinary  conversation.  Many  men  and  many  nations  never 
go  beyond  this.  But  we  are  capable  of  going  beyond  it,  and 
of  passing  from  ordinary  propositions  to  scientific  propo- 
sitions. Experience  at  its  commencement  led  us  to  the  first ; 
prolonged  experience  leads  us  to  the  second.  For  on  apply- 
ing our  primitive  judgment  to  new  instances,  we  find  it  inexact. 
The  child  at  first  concluded  that  all  waters  are  cold ;  if  he 
puts  his  hand  into  a  kettle  just  taken  from  the  fire,  he  changes 
his  opinion  and  no  longer  attributes  cold  to  water,  except  of 
a  certain  temperature.  A  gardener  who  has  never  left  his 
province,  considers  that  all  swans  are  white ;  if  he  is  taken  to 
the  Zoological  Gardens  and  shown  the  black  Australian  swans, 
he  will  no  longer  attribute  whiteness  except  to  a  certain 
variety  of  swans.  A  student  of  botany  thinks  that  all  plants 
with  an  arborescent  bark  arranged  in  concentric  layers  have 
two  cotyledons ;  when  shown  the  dodder  and  two  or  three 
other  kinds,  he  sees  that  the  preceding  law  is  almost  uni- 
versal, but  not  universal. — By  degrees,  owing  to  such  correc- 
tions, our  general  judgments  become  adjusted  to  things.  To 
the  couple  of  abstract  ideas  associated  in  our  minds,  there 
corresponds,  line  for  line,  a  couple  of  abstract  characters 
associated  in  nature ;  henceforward,  in  every  new  instance  we 
observe,  our  proposition  receives  a  new  justification,  and  the 
law  enounced  no  longer  meets  with  exceptions. — At  the 
expiration  of  a  very  long  time,  after  numbers  of  correspond- 
ences thus  verified,  men  of  certain  races  and  of  certain  civi- 
lizations— for  instance,  modern  Europeans — have  ended  by 
believing  that  this  is  so  in  every  case,  that  such  is  the  consti- 
tution of  things,  that  the  whole  of  nature  is  governed  by 
laws,  that  all  its  course  is  uniform,  that  in  every  time  and 
every  place,  in  the  moral  as  well  as  in  the  physical  world, 
when  any  character  is  given,  there  is  necessarily  another 


4I2  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

which  is  connected  with  it.  Is  this  supposition  true  ?  Have 
we  here  a  wholly  universal  law?  We  shall  inquire  into  this 
later  on. — Meanwhile,  we  are  able,  from  the  vast  number  of 
ascertained  laws  within  us  and  about  us,  to  admit  that  it  is  so 
for  our  little  universe,  or  at  all  events  to  avail  ourselves  of  it 
on  occasion  as  an  instrument  of  research,  to  discover  the 
unknown  character  which  we  suppose  to  be  attached  to  the 
known  character,  remembering  that  we  have  in  every  case 
to  verify  our  success  or  failure  by  the  conformity  or  diver- 
gence of  the  supposition  we  have  admitted  and  the  subsequent 
facts.  Thus  it  is  we  inquire,  and  our  different  modes  of 
inquiry  in  this  route  are  the  different  processes  of  scientific 
Induction. 

II.  We  begin  then  with  an  hypothesis,  but  with  a  very 
probable  hypothesis,  warranted  by  a  multitude  of  precedents, 
and  capable,  moreover,  of  being  invalidated  or  confirmed 
after  we  have  availed  ourselves  of  it,  therefore  as  well  selected 
as  possible  to  put  us  in  the  right  road,  and  to  warn  us  off  the 
wrong  road  if  we  happen  to  be  led  into  it ;  this  hypothesis 
being  that  a  character,  taken  apart,  has  an  influence  ;  by 
itself  and  by  itself  alone,  it  involves  something  else,  either 
contemporary,  antecedent,  or  consequent ;  it  is  sufficient  for 
it  to  be  given  for  one  or  more  other  characters  to  be  also 
given. 

Observe  this  word  it  is  sufficient.  It  is  the  key  of  the  door ; 
for  it  puts  in  our  hand  a  property  of  the  unknown  character, 
a  kind  of  distinctive  mark,  by  means  of  which  we  shall  recog- 
nize it ;  since  the  fact  of  the  presence  of  the  other  is  sufficient 
to  give  us  this,  we  shall  recognize  by  this  characteristic  that  it 
is  present  in  all  the  cases  in  which  the  other  is  present ;  in 
none  of  these  cases  can  it  fail.  This  is  its  special  sign,  and, 
so  to  speak,  the  ticket  which  denotes  it  from  all  other  things. 
Hence  a  first  method,  termed  by  Mill  The  Method  of  Agree- 
ment. We  collect  many  cases  in  which  the  known  character 
is  given  ;  according  to  what  has  just  been  said,  the  unknown 
character  is  met  with  in  them  all ;  in  other  words,  it  is  com- 
mon to  them  all,  and  is,  therefore,  found  comprised  in  the  por- 
tion which  is  common  to  them. — Here,  we  choose  cases  as 
dissimilar  as  possible,  and  take  away  their  differences.  The 


CHAP.  II.]  GENERAL   JUDGMENTS. 

greater  and  more  numerous  their  differences,  the  smaller  will 
be  the  common  remnant  left  by  the  elimination ;  as  this  rem- 
nant is  the  only  common  part,  it  necessarily  comprises  the 
character  we  are  in  search  of,  and  if  after  this  elimination 
there  remains  a  single  character  only,  this  single  character  is 
necessarily  the  character  we  are  in  search  of. 

Thus,  take  all  animals  with  mammae,  and  especially  the 
most  widely  different  ones,  the  whale,  the  bat,  the  monkey, 
the  horse,  the  rat,  the  ornithorynchus,  and  exclude  their  dif- 
ferences. After  this  enormous  elimination,  there  will  only  re- 
main a  small  number  of  common  characters,  double  circula- 
tion, the  circumscription  of  the  lungs  by  a  pleura,  the  property 
of  bringing  forth  the  young  alive  ;  either  this  entire  group  or 
some  element  of  it,  among  others  the  last,  is  evidently  the 
character  we  are  in  search  of;  in  fact,  the  last  invariably  ac- 
companies the  possession  of  mammse. — Let  us  collect  a  num- 
ber of  oils  as  different  as  possible,  of  alkaline  substances  as 
different  as  possible,  and  combine  them ;  here  is  the  known 
antecedent.  Now  let  us  seek  for  the  known  consequent,  and, 
for  this,  let  us  compare  together  their  different  products.  If 
we  set  aside  their  differences,  we  shall  find  one  common  char- 
acter only,  that  of  being  a  soap  ;  this,  then,  is  the  character 
which  is  connected  as  consequent  to  the  presence  of  the  given 
antecedent. — Let  us  now  take  a  known  and  well-defined  con- 
sequent, the  sensation  of  sound.*  To  find  its  antecedent,  we 
collect  many  cases  in  which  a  healthy  ear  perceives  a  sound, 
the  sound  produced  by  a  bell,  by  a  string  which  is  pinched  or 
rubbed  by  a  bow,  the  sound  of  a  beaten  drum,  of  a  horn  which 
is  blown,  the  sound  of  the  human  voice,  the  sound  heard  when 
the  head  is  under  water,  or  on  putting  the  ear  to  a  beam  which 
is  slightly  struck,  etc.  After  a  long  examination,  we  discover 
that  all  these  cases  agree,  as  far  as  we  can  judge,  in  one  single 
point,  which  is  the  presence  of  a  reciprocating  movement,  in 
other  words,  of  a  vibration  of  the  sonorous  body,  comprised 
between  certain  limits  of  slowness  and  rapidity,  and  prop- 
agated through  a  medium  to  the  auditory  organ.  This 


*  Ordinary  Sound,  that  is  to  say,  excited  by  an  external  antecedent,  and  not 
the  subjective  sound  excited  by  a  spontaneous  state  of  the  auditor)'  organ. 


414  THE  KNOWLEDGE  OF  GENERAL    THINGS.       [BOOK  IV. 

transmitted   vibration,  then,  is    the  antecedent  we    are  in 
search  of. 

Such  is  the  first  method ;  by  it  we  exclude  the  differences 
of  the  cases  in  question,  which  sets'apart  their  resemblances. 
It  requires  as  preliminary,  the  collection  of  many  cases  in 
which  the  known  character  is  given.  It  adopts  as  a  guide,  the 
necessary  presence  of  the  unknown  character  in  all  cases  in 
which  the  known  character  is  found.  It  has  for  its  auxiliary, 
the  greatest  possible  difference  of  appearance  between  the 
cases.  It  has  for  its  object,  the  severance  of  their  agreements. 
It  has,  as  its  effect,  the  isolation  of  a  remnant,  which  is,  in 
whole  or  part,  the  character  we  are  in  search  of. 

We  have  only  to  invert  this  method  to  possess  another, 
termed  by  Mill  The  Method  of  Difference.  Let  there  be  a 
known  character,  and  take  two  cases ;  the  first  in  which  it  is 
given,  the  second  in  which  it  is  not  given.  Since,  by  its  pres- 
ence alone,  it  introduces  an  unknown  character,  when  absent 
it  will  not  introduce  this ;  this  character  which  it  would  have 
introduced,  will  be  wanting,  and,  therefore,  will  not  be  found 
in  the  second  case.  Here  is  a  new  property  of  the  unknown 
character,  a  second  distinctive  characteristic,  by  means  of 
which  we  shall  be  able  to  discover  it  ;  we  shall  recognize  it  by 
the  mark,  that,  being  present  in  the  first  case,  it  is  absent  in 
the  second. — Here  we  choose  two  cases  as  similar  as  possible. 
Since  it  is  present  in  the  one  and  absent  in  the  other,  it  cannot 
be  one  of  the  characters  in  which  they  are  alike,  and  must 
necessarily  be  one  of  the  characters  in  which  they  differ.  Let 
us  exclude,  then,  all  the  characters  in  which  they  are  alike ; 
the  remainder  is  the  sum  of  their  differences  ;  and  it  is  in  this 
remainder  that  the  character  we  are  in  search  of  is  necessarily 
comprised.  But  this  remainder  is  very  small,  since  we  have 
chosen  the  two  cases  as  much  alike  us  possible ;  if,  therefore, 
this  remainder  consists  in  one  single'character,  this  character 
is  necessarily  the  one  we  are  in  search  of. 

Thus,  take  a  known  character,  extreme  hardness,  or  the 
capacity  of  scratching  all  other  bodies.  We  take  two  bodies 
as  much  alike  as  possible,  one  in  which  the  character  is  pres- 
ent, the  other  in  which  it  is  absent ;  one  of  these  bodies  is  a 
diamond  which  is  pure  carbon ;  the  other  is  purified  carbon  ; 


CHAP.  II.]  GENERAL    JUDGMENTS. 

or,  better  still,  let  one  body  be  a  particular  diamond,  the 
other  the  same  diamond  burnt  and  reduced  to  the  state  of 
cinder.  Chemical  properties,  weight,  component  molecules, 
many  characters,  and  those  the  most  important  of  all,  are 
exactly  alike  in  the  two  cases.  We  eliminate  them,  and  have 
as  residue  a  group  of  characters  which  are  present  in  the  dia- 
mond and  absent  in  the  piece  of  coke,  brilliancy,  transpar- 
ency, octohedric  form,  crystalline  structure.  It  is  this  whole 
group,  then,  or  an  element  of  this  group,  and  especially  the 
last,  which  is  the  character  we  are  in  search  of;  in  fact,  the 
other  elements  of  the  group  are  nothing  more  than  various 
aspects  of  the  last,  and  in  carbon,  crystalline  structure  inva- 
riably accompanies  extreme  hardness. — Again,  when  given 
the  sensation  of  sound,  let  us  select  two  cases,  one  in  which 
it  is  produced,  the  other  in  which  it  is  not  produced,  and  let 
us  select  them  so  very  similar  as  to  differ  in  a  very  small 
number  of  characters  only,  and,  if  possible,  in  one  character 
alone.  For  this  purpose,  let  us  repeat  the  same  case  twice, 
and  introduce  or  suppress  on  the  second  occasion  a  single 
well-defined  circumstance  ;  this  added  or  excluded  circum- 
stance, being  the  only  difference  separating  the  two  cases, 
will  be  the  character  we  are  in  search  of.  For  instance,  in 
the  case  of  the  continuous  sound  produced  by  a  vibrating 
tuning-fork,  we  touch  lightly  the  little  blades,  this  stops  their 
vibration,  and  the  sound  at  once  ceases.  In  the  case  of  a  bell 
struck  by  its  clapper,  we  put  it  under  the  receiver  of  an  air- 
pump  and  exhaust  the  air,  and  the  sound  at  once  ceases.  In 
the  case  of  the  silent  tuning-fork,  we  press  it  and  suddenly 
let  go  the  blades,  which  restores  their  vibrat'on,  the  sound 
at  once  recommences.  In  the  case  of  the  clapper  silently 
striking  the  bell,  we  let  the  air  into  the  receiver,  the  sound 
at  once  recommences.  Here  the  only  circumstance  in  turn 
introduced  or  suppressed  among  the  antecedents  of  the  sound 
is  the  rapid  reciprocating  movement  in  the  case  of  the  tuning- 
fork,  and  the  presence  of  the  elastic  medium  in  the  case  of 
the  bell.  This  double  circumstance,  then,  is  the  only  char- 
acter by  which  the  case  in  which  the  sound  is  present,  dif- 
fers from  the  case  'in  which  the  sound  is  wanting,  hence  it 
follows  that  it  is  the  antecedent  we  are  in  search  of. 


41 6          THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

Such  is  the  second  method ;  by  it  we  exclude  the  resem 
blances  of  the  cases  considered,  and  so  set  apart  their  differ- 
ences. It  requires  as  preliminary  the  selection  of  two  cases 
distinguished,  one  by  the  presence,  the  other  by  the  absence, 
of  the  known  character.  It  adopts  as  a  guide  the  necessary 
absence  of  the  unknown  character  in  all  the  cases  in  which 
the  known  character  is  absent.  It  has,  for  its  auxiliary,  the 
greatest  possible  resemblance  between  the  two  cases.  It  has, 
for  its  object,  the  severance  of  differences.  It  has  as  its  ef- 
fect the  isolation  of  a  remnant,  which  is,  in  whole  or  part,  the 
character  we  are  in  search  of. 

These  two  methods  suggest  a  third,  termed  by  Mill,  The 
Method  of  Concomitant  Variations,  To  the  two  marks  by 
which  we  make  discovery  of  the  unknown  character,  it  adds  a 
a  new  one.  We  have  recognized  it  by  the  characteristic  of 
its  presence  whenever  the  known  character  is  present,  and  by 
the  characteristic  of  its  absence  whenever  the  known  charac- 
ter is  absent ;  we  can  also  recognize  it  by  the  characteristic 
that,  whenever  the  known  character  varies,  the  unknown  char- 
acter also  varies  in  a  corresponding  manner.  In  fact,  in  one 
aspect  or  another,"*  the  known  character  may  be  considered 
as  a  sum  of  degrees,  each  of  which  taken  apart  has  its  influ- 
ence ;  for  if  each  taken  apart  had  no  influence  whatever,  we 
might  successively  suppress  them  all  up  to  the  last,  and, 
therefore,  suppress  the  character  itself,  without  suppressing 
its  influence  ;  we  might  also  add  them  all,  one  after  another, 
up  to  a  certain  limit,  and,  therefore,  reconstitute  the  charac- 
ter itself  as  fully  as  we  pleased,  without  re-constituting  its 
influence.  Now  these  two  suppositions  are  contrary  to  the 
notion  of  the  character  as  we  have  assumed  it.  Thus,  from 


*  For  instance,  in  the  corresponding  variations  which  the  form  of  the  teeth, 
the  structure  of  the  condyle,  the  length  of  the  intestines,  and  the  arrangement  of 
the  limbs,  undergo  in  different  species,  the  observed  organ  becomes  more  or  less 
fitted  or  unfitted  for  carnivorous  or  herbivorous  life  ;  the  degree  of  fitness  for  car- 
nivorous life  being  lowered  in  proportion  as  the  degree  of  fitness  for  herbivorous 
life  increases.  In  this  double  sense,  an  organ  may  be  considered  in  the  aspect  of 
its  quantity,  and  may  present  a  sum  of  greater  or  less  degrees.  Hence,  the 
methods  of  Cuvier  for  determining  unknown  organs  from  their  dependence  with 
relation  to  known  organs. 


CHAP.  II.]  GENERAL  JUDGMENTS.  417 

this  very  notion,  we  may  conclude  that  every  variation  of  the 
known  character  involves  a  variation  of  the  unknown  charac- 
ter, and  on  this  indication,  may  seek  for  the  unknown  char- 
acter. 

For  instance,  take  a  known  character,  the  progressive  re- 
tardation, and  consequent  final  extinction,  of  the  movement 
of  the  pendulum.  We  cannot  construct  a  pendulum  to  oscil- 
late for  ever,  and  consequently  cannot  find  a  second  case  in 
which  the  known  character  is  absent.  For  this  impracticable 
case  of  absence  of  retardation,  we  substitute  a  number  of 
practical  cases  of  diminished  retardation.  We  diminish  more 
and  more  the  obstacles  the  pendulum  meets  with,  and  find 
that  its  retardation  is  proportionately  diminished.  When 
the  friction  at  the  point  of  suspension  is  reduced  as  much  as 
possible,  and  when  the  surrounding  air  is  exhausted  as  much 
as  possible,  it  takes  thirty  hours,  instead  of  some  minutes,  for 
the  movement  to  stop.  In  proportion  as  the  obstacles  ap- 
proach the  degree  at  which  they  would  vanish,  the  retarda- 
tion approaches  the  degree  at  which  it  would  vanish.  As  far 
as  we  are  able  to  judge,  there  is,  between  the  first  case  in 
which  the  pendulum  ceases  to  oscillate  after  a  few  minutes, 
and  the  other  cases  in  which  it  continues  its  oscillation  for  a 
longer  and  longer  time,  one  difference  only,  which  is  that, 
in  the  first  case,  the  obstacles  are  greater,  and  that,  in  the 
others,  they  are  less ;  the  presence,  then,  of  an  increase  in 
the  obstacles  is  the  antecedent  of  an  increase  in  the  retarda- 
tion.— But  this  does  not  as  yet  prove  that,  were  there  no 
obstacles,  there  would  be  no  retardation.  For  it  might  hap- 
pen that  the  diminution  of  the  antecedent  and  the  diminu- 
tion of  the  consequent  did  not  proceed  at  the  same  rate ;: 
perhaps,  in  proportion  as  the  resistance  is  diminished  by  one 
half,  the  retardation  is  diminished  only  by  a  fourth  or  other 
smaller  fraction ;  this  would  be  the  case,  if  the  retardation 
had  two  causes,  one  of  which  was  a  property  inherent  to  the 
motion  itself,  that  is  to  say  a  tendency  to  cease  after  the 
lapse  of  a  certain  time,  the  other  appertaining  to  the  circum- 
stances, that  is  to  say  to  the  resistance  of  the  surrounding 
bodies.  In  this  case,  the  complete  suppression  of  the  ob- 
stacles would  only  diminish  the  retardation,  without  wholly 
27 


4i 8  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV 

suppressing  it ;  the  pendulum  would  oscillate  sixty  hours 
and  more,  but  would  finally  stop. — We  must  prove,  then, 
that  the  retardation  diminishes  at  the  same  rate  as  the  re- 
sistance, and  that  every  degree  added  to  or  taken  from  the 
resistance  corresponds  to  an  equal  degree  added  to  or  taken 
from  the  retardation.  This  is  effected  by  the  two  methods 
already  described,  though  seeking,  no  longer  the  antecedent 
of  the  retardation,  but  the  antecedents  of  two  of  its  diminu- 
tions or  augmentations  measured  beforehand,  and  through 
discovering,  by  the  extraction  of  agreements  or  differences, 
that  these  antecedents  are  two  precisely  equal  diminutions 
or  augmentations  introduced  into  the  sum  of  the  resistances 
presented  by  the  surrounding  obstacles.  When  this  is 
established  it  becomes  proved  that,  when  the  resistance 
ceases,  the  retardation  ceases. — This  is  a  proposition  which 
we  were  just  now  unable  to  establish  by  experience :  but 
now  we  have  no  need  to  establish  it  by  experience ;  the  gap 
is  filled  up ;  we  may  dispense  with  observation  ;  we  have  its 
equivalent.  Thanks  to  this  equivalent,  we  know  now  that 
the  case  in  which  the  motion  is  retarded,  and  that  in  which 
it  is  not  retarded,  differ  only  in  one  character,  namely,  the 
resistance  opposed,  in  the  first  case,  by  obstacles ;  hence 
it  follows  that  this  resistance  is  the  antecedent  we  are  in 
search  of. — Such  is  the  third  method  which,  compounded  of 
the  first  and  second,  is  a  substitute  for  the  second,  and  which 
is  often  of  higher  value  than  they  are,  from  its  determining, 
not  only  the  quality,  but  also  the  quantity,  of  the  unknown 
character.* 

All  these  methods  employ  the  same  artifice,  that  is  to 
say  the  elimination  or  exclusion  of  characters  other  than 
the  character  we  are  in  search  of.  Let  us  take  a  known 
character;  it  is  accompanied,  followed,  or  preceded  by  ten 
others.  Which  one  or  more  of  these  ten  are  so  connected 
with  its  presence,  that  its  presence  is  sufficient  to  give  them 
as  its  companions,  antecedents,  or  consequents  ?  All  the 


*  Mill,  after  describing  this  method,  indicates  a  fourth,  which  he  terms  the 
Method  of  Residues.  It  is  but  another  case  of  the  Method  of  Differences,  and  is 
but  rarely  employed.  The  three  which  we  have  explained  had  their  first  origin 
in  Bacon's  "  Tables  of  Presence,  Absence,  and  Degrees." 


CHAP.  II.]  GENERAL   JUDGMENTS. 

difficulty,  and  the  only  possible  solution,  lie  here.  To  resolve 
the  difficulty  and  effect  the  solution,  elimination  is  required, 
that  is  to  say  the  exclusion,  amongst  the  ten  characters,  of 
those  which  are  not  thus  connected  with  the  presence  of  the 
known  character.  But,  as  we  are  not  able  actually  to  exclude 
them,  and  as,  in  nature,  the  character  we  are  in  search  of  is 
always  hidden  in  a  crowd  of  others,  we  collect  cases  which 
by  their  diversity  entitle  the  mind  to  clear  away  this  crowd. 
We  look  for  indications  which  may  enable  us  to  distinguish 
between  the  character  we  are  in  search  of  and  superfluous 
characters.  We  find  three  of  these  indications,  and  apply 
them  ;  for  greater  security,  we  apply  all  three  of  them  suc- 
cessively in  order  that  they  may  correct  one  another.  When 
the  expulsion  is  accomplished,  what  remains  is  the  character 
we  are  in  search  of. 

In  some  cases  these  eliminating  processes  are  ineffectual, 
namely,  in  those  in  which  the  consequent,  though  produced 
by  a  concurrence  of  antecedents,  cannot  be  reduced  into  its 
elements.  Methods  of  isolation  are  then  impracticable  ;  and, 
as  we  can  no  longer  eliminate,  we  can  no  longer  perform 
induction. — Now,  this  grave  difficulty  presents  itself  in  nearly 
all  cases  of  motion  ;  for  nearly  every  motion  is  the  effect  of 
a  concurrence  of  forces,  and  the  respective  effects  of  the 
different  forces  are  found  so  mixed  up  in  it  that  we  cannot 
separate  them  without  destroying  it,  and  it  seems  impossible 
to  know  what  part  each  force  has  in  the  production  of  the 
movement.  Take  a  body  acted  on  by  two  forces  whose 
directions  form  an  angle  ;  it  moves  along  the  diagonal ;  every 
part,  every  moment,  every  position,  every  element  of  its 
movement  is  the  combined  effect  of  the  two  impelling  forces. 
The  two  effects  are  so  intimately  combined  that  we  cannot 
isolate  either  of  them  to  refer  it  to  its  origin. — To  perceive 
each  effect  separately,  we  should  have  to  consider  the  mo- 
tions turned  in  another  direction,  that  is  to  say  to  suppress 
the  given  movement  and  replace  it  by  others.  It  is  the 
double  consequent  of  a  double  antecedent,  and,  as  we  cannot 
isolate  one  or  other  of  its  two  parts,  we  cannot  isolate  one  or 
other  of  the  two  parts  of  its  antecedent.  Neither  the  usual 
method  of  Agreement  or  of  Difference,  nor  the  subsidiary 


420  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

methods  of  Residues  or  of  Concomitant  Variations,  all  of 
which  are  decomposing  and  eliminative,  can  serve  us  in  a 
case  which  by  its  nature  excludes  all  elimination  and  all 
decomposition. — We  must  therefore  evade  the  obstacle,  and 
here  it  is  that  the  Method  of  Deduction — the  last  key  to  Na- 
ture— comes  in.  We  commence  by  borrowing  a  process  from 
the  sciences  of  construction ;  we  leave  the  effect,  we  set  to 
work  beside  it,  we  study  other  simpler  cases ;  we  examine 
various  analogous  effects  or  consequents,  we  connect  each  to 
its  cause  or  antecedent  by  the  processes  of  ordinary  induc- 
tion ;  then,  we  form  a  construction.  We  mentally  collect 
many  of  these  antecedents  or  causes,  and  we  conclude,  from 
their  known  consequents  or  effects,  what  must  be  their  total 
consequent  or  effect.  We  then  verify  if  the  total  effect 
given  is  exactly  similar  to  the  total  effect  predicted,  and,  if 
so,  we  attribute  it  to  the  combination  of  causes  we  have  fabri- 
cated.— Thus,  to  discover  the  causes  of  the  motion  of  the 
planets,  we  establish,  by  simple  inductions,  first,  the  law 
connecting  the  motion  in  direction  of  the  tangent  with  a 
force  of  initial  impulsion,  then,  the  law  connecting  the  fall  of 
a  body  towards  another  with  the  accelerating  force  of  gravity. 
From  these  two  laws  obtained  by  induction,  we  deduce,  by 
calculation,  the  various  positions  and  velocities  which  a  body 
would  assume,  under  the  combined  influences  of  an  initial 
impulsion  and  accelerating  gravity,  and,  after  verifying  that 
the  observed  planetary  motions  coincide  exactly  with  the 
foreseen  motions,  we  conclude  that  the  two  forces  in  question 
are  actually  the  causes  of  the  planetary  motions.  "To  the 
Deductive  Method,"  says  Mill,  "  the  human  mind  is  indebted 
for  its  most  conspicuous  triumphs  in  the  investigation  of 
Nature.  To  it,  we  owe  all  the  theories  by  which  vast  and 
complicated  phenomena  are  embraced  under  a  few  simple 
laws." — It  is  only  a  derivation  of  the  preceding  methods;  for 
it  starts  from  a  property  of  the  antecedent  obtained  by  those 
methods.  This  property  is  that  of  being  sufficient,  that  is  to 
say  of  exciting,  by  its  presence  alone,  a  certain  consequent. 
Therefore,  if  it  be  present,  the  consequent  will  arise  ;  and,  if 
another  antecedent  obtained  in  the  same  way  is  also  present, 
its  consequent  will  similarly  arise  ;  so  that  the  whole  conse- 


CHAP.  II.]  GENERAL  JUDGMENTS.  421 

quent  will  be  mixed  and  double. — If  now  the  whole  conse- 
quent observed  coincides  in  all  its  parts  with  the  whole 
consequent  predicted,  we  shall  say  with  certainty  that  the 
double  antecedent  supposed  is  sufficient  to  cause  it  to  arise, 
and  we  shall  be  able  to  assume  that,  in  the  case  in  question, 
this  double  antecedent  in  fact  exists. — In  truth,  this  will  only 
be  a  supposition  or  hypothesis;  but  it  will  be  the  more 
probable  in  proportion  as  the  total  consequent,  being  more 
complex  and  more  multiplex,  further  limits  the  number  of 
hypothesis  capable  of  accounting  for  it ;  and  it  will  be  wholly 
certain  when,  as  is  the  case  with  the  motion  of  the  planets, 
we  can  demonstrate  that  no  other  combination  of  forces 
could  produce  ft,  that  is  to  say  that  the  double  antecedent 
assumed  is  not  only  possible,  but  alone  possible,  and  there- 
fore, real. 

These  are  the  rules:  an  example  will  make  them  clearer; 
there  is  one  in  which  we  shall  see  all  the  methods  in  exercise 
— Dr.  Well's  theory  of  Dew.  I  shall  cite  the  exact  words  of 
Mill  and  Herschel.*  They  are  so  clear  that  we  must  give 
ourselves  the  pleasure  of  considering  them.  We  must  begin 
by  separating  dew  from  rain,  and  the  moisture  of  fogs,  and 
by  defining  it  as  "  the  spontaneous  appearance  of  moisture 
on  substances  exposed  in  the  open  air,  when  no  rain  or  visible 
wet  is  falling."  What  is  the  cause  of  the  phenomenon  we 
have  thus  defined,  and  how  was  that  cause  discovered  ? 

In  the  first  place,  " '  we  have  analogous  phenomena  in 
the  moisture  which  bedews  a  cold  metal  or  stone  when  we 
breathe  upon  it ;  that  which  appears  on  a  glass  of  water  fresh 
from  the  well  in  hot  weather ;  that  which  appears  on  the  in- 
side of  windows  when  sudden  rain  or  hail  chills  the  external 
air ;  that  which  runs  down  our  walls  when,  after  a  long  frost, 
a  warm  moist  thaw  comes  on.'  Comparing  these  cases,  we 
find  that  they  all  contain  the  phenomenon  which  was  pro- 
posed as  the  subject  of  investigation.  Now,  '  all  these  in- 
stances agree  on  one  point — the  coldness  of  the  object  dewed, 
in  comparison  with  the  air  in  contact  with  it.'  Bat  there 


*  Mill,  "  Logic,"  4th  edition,  i.  451-8, citing  from  Sir  J.  Herschel,  "Discourse 
on  the  Study  of  Natural  Philosophy." 


422  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

still  remains  the  most  important  case  of  all,  that  of  noctur- 
nal dew :  does  the  same  circumstance  exist  in  this  case  ? 
'  Is  it  a  fact  that  the  object  dewed  is  colder  than  the  air  ? 
Certainly  not,  one  would  at  first  be  inclined  to  say ;  for  what 
is  to  make  it  so  ?  But  .  .  .  the  experiment  is  easy  :  we  have 
only  to  lay  a  thermometer  in  contact  with  the  dewed  sub- 
stance, and  to  hang  one  at  a  little  distance  above  it,  out  of 
reach  of  its  influence.  The  experiment  has  therefore  been 
made;  the  question  has  been  asked,  and  the  answer  has  been 
invariably  in  the  affirmative.  Whenever  an  object  contracts 
dew,  it  is  colder  than  the  air.' 

"  Here  then  is  a  complete  application  of  the  Method  of 
Agreement,  establishing  the  fact  of  an  invariable  connection 
between  the  deposition  of  dew  on  a  surface,  and  the  coldness 
of  that  surface  compared  with  the  external  air.  But  which 
of  these  is  cause,  and  which  effect  ? — or  are  they  both  effects 
of  something  else?  On  this  subject,  the  Method  of  Agree- 
ment can  afford  us  no  light :  we  must  call  in  a  more  potent 
method.  '  We  must  collect  more  facts,  or,  which  comes  to 
the  same  thing,  vary  the  circumstances  ;  since  every  instance 
in  which  the  circumstances  differ  is  a  fresh  fact :  and  es- 
pecially we  must  note  the  contrary  or  negative  cases,  i.  e., 
where  no  dew  is  produced : '  a  comparison  between  instances 
of  dew,  and  instances  of  no  dew,  being  the  condition  neces- 
sary to  bring  the  Method  of  Difference  into  play. 

" '  Now,  first,  no  dew  is  produced  on  the  surface  of  pol- 
ished metals,  but  it  is  very  copiously  on  glass.'  Here  is  an 
instance  in  which  the  effect  is  produced,  and  another  instance 
in  which  it  is  not  produced.  .  .  .  But,  as  the  differences  be- 
tween glass  and  polished  metal  are  manifold,  the  only  thing 
we  can  as  yet  be  sure  of  is,  that  the  cause  of  dew  will  be 
found  among  the  circumstances  by  which  the  former  sub- 
stance is  distinguished  from  the  latter.  .  .  .  To  detect  this 
particular  circumstance  of  difference  we  have  but  one  practi- 
cable method  —  that  of  Concomitant  Variations.  'In  the 
cases  of  polished  metal  and  polished  glass,  the  contrast  shows 
evidently  that  the  substance  has  much  to  do  with  the  phe- 
nomenon, therefore  let  the  substance  alone  be  diversified  as 
much  as  possible,  by  exposing  polished  surfaces  of  various 


CHAP.  II.]  GENERAL  JUDGMENTS.  423 

kinds.  This  done,  a  scale  of  ititensity  becomes  obvious. 
Those  polished  substances  are  found  to  be  most  strongly 
dewed  which  conduct  heat  worst ;  while  those  which  conduct 
well,  resist  dew  most  effectually.'  Hence  we  conclude  that 
the  deposition  of  dew  is  in  some  way  connected  with  the 
power  which  the  body  possesses  of  resisting  the  passage  of 
heat. 

" '  But,  if  we  expose  rough  surfaces  instead  of  polished, 
we  sometimes  find  this  law  interfered  with.  Thus,  roughened 
iron,  especially  if  painted  over  or  blackened,  becomes  dewed 
sooner  than  varnished  paper ;  the  kind  of  surface,  therefore, 
has  a  great  influence.  Expose,  then,  the  same  material  in 
very  diversified  states  as  to  surface,'  (that  is,  employ  the 
Method  of  Difference  to  ascertain  concomitance  of  varia- 
tions,;) '  and  another  scale  of  intensity  becomes  at  once  ap- 
parent ;  those  surfaces  which  part  with  their  heat  most  readily 
by  radiation,  are  found  to  contract  dew  most  copiously.' 
Hence  we  conclude  that  the  deposition  of  dew  is  also  in  some 
way  connected  with  the  power  of  radiating  heat. 

" '  Again,  the  influence  ascertained  to  exist  of  substance 
and  surface  leads  us  to  consider  that  of  texture :  and  here, 
again,  we  are  presented  on  trial  with  remarkable  differences, 
and  with  a  third  scale  of  intensity,  pointing  out  substances 
of  a  close  firm  texture,  such  as  stones,  metals,  etc.,  as  un- 
favorable, but  those  of  a  loose  one,  as  cloth,  velvet,  wool, 
eider-down,  cotton,  etc.,  as  eminently  favorable  to  the  con- 
traction of  dew.'  Looseness  of  texture,  therefore,  or  some- 
thing which  is  the  cause  of  that  quality,  is  another  circum- 
stance which  promotes  the  deposition  of  dew  ;  but  this  third 
cause  resolves  itself  into  the  first,  viz.,  the  quality  of  resist- 
ing the  passage  of  heat ;  for  substances  of  loose  texture  '  are 
precisely  those  which  are  best  adapted  for  clothing,  or  for 
impeding  the  free  passage  of  heat  from  the  skin  into  the  air, 
so  as  to  allow  their  outer  surfaces  to  be  very  cold,  while  they 
remain  warm  within.' 

"  It  thus  appears  that  the  instances  in  which  much  dew 
is  deposited,  which  are  very  various,  agree  in  this,  and,  so 
far  as  we  are  able  to  observe,  in  this  only,  that  they  either 
radiate  heat  rapidly  or  cond  act  it  slowly :  qualities  between 


424  THE  KNO  WLEDGE   OF  GENERAL    THINGS.     [BOOK  IV. 

which  there  is  no  other  circumstance  of  agreement,  than 
that  by  virtue  of  either,  the  body  tends  to  lose  heat  from  the 
surface  more  rapidly  than  it  can  be  restored  from  within. 
The  instances  on  the  contrary,  in  which  no  dew,  or  but  a 
small  quantity  of  it,  is  formed,  and  which  are  also  extremely 
various,  agree  (as  far  as  we  can  observe)  in  nothing  except  in 
not  having  this  same  property."  We  can  now  revert  to  our 
previous  inquiry,  as  to  whether  the  coldness  was  the  cause  of 
dew,  or  its  effect.  "  This  doubt  we  are  now  able  to  resolve. 
We  have  found  that,  in  every  such  instance,  the  substance 
on  which  dew  is  deposited  is  one  which,  by  its  own  properties 
or  laws,  would,  if  exposed  in  the  night,  become  colder  than 
the  surrounding  air.  The  coldness,  therefore,  being  accounted 
for  independently  of  the  dew,  while  it  is  proved  that  there  is 
a  connection  between  the  two,  it  must  be  the  dew  that  de- 
pends on  the  coldness ;  or,  in  other  words,  the  coldness  is  the 
cause  of  the  dew. 

"  This  law  of  causation,  already  so  amply  established,  ad- 
mits, however,  of  efficient  additional  corroboration  in  no  less 
than  three  ways.  First,  by  deduction  from  the  known  laws 
of  aqueous  vapor  when  diffused  through  air,  or  any  other  gas. 
...  It  is  known  by  direct  experiment  that  only  a  limited 
quantity  of  water  can  remain  suspended  in  the  state  of  vapor 
at  each  degree  of  temperature,  and  that  this  maximum  grows 
less  and  less  as  the  temperature  diminishes.  From  this  it 
follows,  deductively,  that  if  there  is  already  as  much  vapor 
suspended  as  the  air  will  contain  at  its  existing  temperature, 
any  lowering  of  that  temperature  will  cause  a  portion  of  the 
vapor  to  be  condensed,  and  become  water.  But,  again,  we 
know  deductively,  from  the  laws  of  heat,  that  the  contact  of 
the  air  with  a  body  colder  than  itself,  will  necessarily  lower 
the  temperature  of  the  stratum  of  air  immediately  applied  to 
its  surface ;  and  will  therefore  cause  it  to  part  with  a  portion 
of  its  water,  which  accordingly  will,  by  the  ordinary  laws  of 
gravitation  or  cohesion,  attach  itself  to  the  surface  of  the 
body,  thereby  constituting  dew.  This  deductive  proof  has 
the  advantage  that  it  accounts  for  the  exceptions  to  the  occur- 
rence of  the  phenomenon,  the  cases  in  which,  although  the 
body  is  colder  than  the  air,  yet  no  dew  is  deposited ;  by  show- 


CHAP.  II.]  GENERAL   JUDGMENTS.  425 

ing  that  this  will  necessarily  be  the  case  when  the  air  is  so 
under-supplied  with  aqueous  vapor,  comparatively  to  its 
temperature,  that  even  when  somewhat  cooled  by  the  contact 
of  the  colder  body,  it  can  still  continue  to  hold  in  suspension 
all  the  vapor  which  was  previously  suspended  in  it :  thus  in 
a  very  dry  summer  there  are  no  dews,  in  a  very  dry  winter 
no  hoar-frost. 

"  The  second  corroboration  of  the  theory  is  by  direct  ex- 
periment, according  to  the  canon  of  the  Method  of  Differ- 
ence. We  can,  by  cooling  the  surface  of  any  body,  find  in  all 
cases  some  temperature  at  which  dew  will  begin  to  be  de- 
posited. We  can,  it  is  true,  accomplish  this  only  on  a  small 
scale  ;  but  we  have  ample  reason  to  conclude  that  the  same 
operation,  if  conducted  in  Nature's  great  laboratory,  would 
equally  produce  the  effect. 

"  And  finally,  even  on  that  great  scale  we  are  able  to 
verify  the  result.  The  case  is  one  of  those  rare  cases,  as 
we  have  shown  them  to  be,  in  which  Nature  works  the 
experiment  for  us  in  the  same  manner  in  which  we  ourselves 
perform  it ;  introducing  into  the  previous  state  of  things  a 
single  and  perfectly  definite  new  circumstance,  and  manifest- 
ing the  effect  so  rapidly  that  there  is  not  time  for  any  other 
material  change  in  the  pre-existing  circumstances.  '  It  is 
observed  that  dew  is  never  copiously  deposited  in  situations 
much  screened  from  the  open  sky,  and  not  at  all  in  a 
cloudy  night ;  but  if  the  clouds  withdraw  even  for  a  few  min- 
utes, and  leave  a  clear  opening,  a  deposition  of  dew  presently 
begins,  and  goes  on  increasing.'  .  .  .  The  proof,  therefore,  is 
complete,  that  the  presence  or  absence  of  an  uninterrupted 
communication  with  the  sky  causes  the  deposition  or  non- 
deposition  of  dew.  Now,  since  a  clear  sky  is  nothing  but  the 
absence  of  clouds,  and  it  is  a  known  property  of  clouds,  as  of 
all  other  bodies  between  which  and  any  given  object  noth- 
ing intervenes  but  an  elastic  fluid,  that  they  tend  to  raise  or 
keep  up  the  superficial  temperature  of  the  object  by  radia- 
ting heat  to  it,  we  see  at  once  that  the  disappearance  of 
clouds  will  cause  the  surface  to  cool ;  so  that  Nature,  in  this 
case,  produces  a  change  in  the  antecedent  by  definite  and 
known  means,  and  the  consequent  follows  accordingly :  a 


426  THE   KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

natural  experiment  which  satisfies  the   requisitions  of  the 
Method  of  Difference." 


§  II.  LAWS  CONCERNING  .POSSIBLE  THINGS. 

I.  We  see  that  this  process  is  of  considerable  length ;  for 
it  requires  the  collection,  selection,  and  comparison  of  many 
instances.     Further  than  this,  it  usually  happens  that  the 
more  general  the  law,  the  more  time  is  required  to  obtain  it ; 
for   it   requires  the  preliminary   discovery  of  many  partial 
laws ;  Newton,  Geoffrey,  Saint-Hilaire,  Dalton,  Faraday  are 
but  the  successors  of  many  others,  and  the  most  extensive 
inductive  law  we  are  acquainted  with,  that  which  states  the 
Conservation  of  Force,  is  of  yesterday's  discovery.*     Again, 
however  well-established  and  verified  one  of  these  laws  may 
be,  if  we  wish  to  apply  it  outside  of  the  little  circle  of  space 
and  short  fragment  of  duration  to  which  our  observations  are 
limited,  it  becomes  probable  only.     It  is  not  absolutely  cer- 
tain that  the  Law  of  Gravitation  continues  to  hold  good,  be- 
yond the  furthest  nebulae  of  Herschel.     It  is  not  at  all  cer- 
tain that,  in  the  sun,  hydrogen  and  oxygen  preserve  the 
chemical  affinity  which  we  find  they  have  herewith  us.     It  is 
possible  that  the  intense  temperature  in  the  sun,  that  some 
unknown  circumstance  beyond  the  furthest  nebulas,  may  in- 
tervene to  alter  or  annul  these  laws.     Consequently,  on  con- 
sidering the  proposition  enouncing  it,  we  find,  on  the  one 
hand,  that  its  acquisition  is  tardy,  on  the  other,  that  its  ap- 
plication is  limited. 

II.  Such  are  the  distinctive  characteristics  of  the  general 
proposition  whose  component  ideas,  being  formed  by  extrac- 
tion and  gradually  adjusted  to  the  general  characters  of  real 
things,  are  bound  to  correspond  with  their  object. — Very  dif- 
erent  are  the  distinctive  characteristics  of  the  general  prop- 
ositions whose  component  ideas,  being  formed  by  construc- 
tion, are  not  subject  to  a  similar  obligation.     Such  are  the 
ideas  of  arithmetic,  of  geometry,  of  pure  mechanics,  of  all 

*  See,  as  to  the  order  of  these  discoveries,  the  valuable  work  of  Dr.  Whewell. 
on  the  "  History  of  the  Inductive  Sciences." 


CHAP.  II.]  GENERAL   JUDGMENTS.  427 

the  mathematical  sciences,  and,  more  generally,  of  all  the  de- 
ductive sciences.  The  propositions  of  these  sciences  are  not 
merely  probable,  but  certain  beyond  our  little  world ;  at  all 
events,  we  believe  it  to  be  so,  and,  moreover,  are  unable  to 
believe  or  conceive  that  it  is  otherwise.  Even  beyond  the 
furthest  nebulae,  two  facts  or  objects  added  to  three  facts  or 
objects  of  the  same  class  make  five  facts  or  objects  of  the 
same  class  ;  if  a  triangle  be  found  there,  its  angles  are,  as  with 
us,  together  equal  to  two  right  angles  ;  if  a  body  be  impelled 
by  two  forces  whose  directions  form  an  angle,  it  will  move, 
as  with  us,  along  their  diagonal.  At  all  events,  whatever 
effort  we  may  make  to  conceive  the  contrary,  we  cannot  do 
so  ;  the  two  component  ideas  of  the  proposition,  once  well 
understood,  form  in  our  mind  an  indissoluble  couple  whose 
terms,  in  themselves,  refuse  separation. — Besides,  the  most 
general  of  these  propositions  are  the  ones  which  are  first  dis- 
covered ;  for  it  is  by  their  means  that  we  prove  the  less  gen- 
eral ones.  Looked  at  geometrically,  the  idea  of  a  solid  is  less 
general  than  that  of  a  surface,  and  that  of  a  surface  less  gen- 
eral than  that  of  a  line,  since  the  solid  is  constructed  with 
surfaces,  and  the  surface  with  lines,  whence  it  follows  that 
we  find,  mentally  at  least,  if  not  in  nature,  the  surface  with- 
out the  solid,  and  the  line  without  the  surface,  but  never  the 
solid  without  the  surface,  or  the  surface  without  the  line ;  so 
that  the  surface  occurs  more  frequently  than  the  solid,  and 
the  line  more  frequently  than  the  surface.  Now  we  all  know 
that,  to  establish  propositions  relating  to  solids,  we  must 
first  establish  those  relating  to  surfaces,  and  that,  to  establish 
propositions  relating  to  surfaces,  we  must  first  establish  those 
relating  to  lines. — Finally,  among  the  most  general  of  these 
propositions,  there  are  certain  ones,  called  axioms,  which  we 
do  not  demonstrate,  and  by  which  we  demonstrate  the  rest. 
We  fix  them  at  the  head  of  every  science,  like  hooks  from 
which  the  other  propositions  may  depend.  These  others  are 
so  many  links,  forming  one  or  more  chains  ;  each  link  in  them 
is  hung  from  the  one  preceding  it,  and  sustains  the  one  suc- 
ceeding it ;  but  the  supports  which  bear  the  whole  are  two, 
three,  or  four  expressed  or  implied  propositions,  placed  at 
the  summit.  If  we  do  not  demonstrate  them,  it  is  because 


428  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

we  pronounce  them  evident  in  themselves ;  at  least,  it  seems 
to  the  attentive  reader  that  he  requires  no  proof  to  admit 
them,  but  that  it  is  enough  for  him  to  understand  them.  As 
soon  as  the  two  component  ideas  of  the  proposition  are  clear 
to  his  mind,  they  become  mutually  attached  there,  and  form 
a  couple  ;  this  reciprocal  consolidation  is  instantaneous  ;  every 
one  sees  at  first  sight  that,  among  all  the  lines  drawn  from 
one  point  to  another,  the  straight  line  is  the  shortest.  So, 
too,  in  every  other  deductive  science,  there  are  certain  primi- 
tive ideas  which,  once  present  in  the  mind,  become  fitted  to 
one  another  as  speedily,  with  as  invincible  a  link,  with  as  un- 
contested  authority.  Here,  indeed,  are  propositions  fashioned 
in  a  strange  way,  and  these  are  what  we  are  now  about  to 
examine. 

III.  For  propositions  of  this  kind,  there  are  two  kinds  of 
proof:  the  one,  experimental,  inductive,  approximative,  and 
slow  ;  the  other  analytical,  deductive,  precise,  and  short ;  it 
is  this  last  of  which  we  avail  ourselves  in  all  the  sciences  of 
construction. — The  better  to  mark  out  the  characters  and  con- 
trasts of  these  two  kinds  of  proofs,  the  reader  must  allow  me 
to  make  a  supposition.  Take  a  proposition  closely  bordering 
on  an  axiom,  that  truth  of  elementary  geometry  that,  in  every 
triangle,  the  sum  of  the  angles  is  equal  to  two  right  angles.  Let 
us  imagine  a  man  not  a  geometrician,  and  incapable,  by  the 
structure  of  his  brain,  of  becoming  one,  but  very  patient,  very 
precise,  and  very  skilful  at  induction.  I  put  in  his  hand  a  semi- 
circle divided  into  minutes  and  degrees  so  as  to  measure  an- 
gles ;  I  trace  before  him  a  number  of  triangles  ;  I  teach  him 
to  trace  others,  and  I  ask  him  to  investigate  whether,  in  all 
these  triangles,  the  sum  of  the  angles  is  not  equal  to  a  certain 
number  of  right  angles. — For  several  days,  he  applies  his  semi- 
circle to  the  angles  of  three  or  four  hundred  triangles ;  in 
each  case,  he  observes  by  his  semicircle  the  magnitudes  of  the 
three  angles,  and,  by  adding  their  values,  invariably  finds 
that  their  sum  amounts  to  180°,  that  is,  to  two  right  angles. 
This  interests  him,  and  he  attempts  to  discover  the  partial 
laws  of  which  this  law,  obtained  by  the  collection  of  agree- 
ments, is  the  total. — He  first  takes  triangles  having  one  right 
angle  ;  the  sum  of  the  other  two  angles  is  then  equal  to  one 


CHAP.  II.]  GENERAL  JUDGMENTS.  429 

right  angle,  and  it  will  be  easier  to  find  the  circumstance  which 
causes  this  equality.  He  goes  to  work  again  with  his  semi- 
circle, and  proves  that,  as  the  first  of  these  two  angles  ap- 
proaches a  right  angle  in  magnitude,  the  second  of  them  dif- 
fers from  a  right  angle  in  magnitude,  so  that  the  diminution  of 
the  one  is  compensated  by  the  augmentation  of  the  other, 
and  that,  by  means  of  this  perpetual  compensation,  the  sum 
of  the  two  angles  is  always  equal  to  a  right  angle. — He  then 
takes  other  triangles  having  an  angle  of  the  same  magnitude ; 
then,  measuring  this  angle,  he  calculates  by  subtraction  the 
value  which  the  two  other  angles  must  together  have  to  form 
with  it  a  magnitude  equal  to  two  right  angles.  Then  apply- 
ing once  more  his  semicircle,  he  proves  that,  whenever  the 
first  of  these  two  angles  approaches  the  required  amount,  the 
second  proportionately  differs  from  it,  in  such  a  way  that,  the 
loss  being  equal  to  the  gain,  the  sum  of  the  two  angles  is  al- 
ways equal  to  the  required  magnitude. — Thus,  in  all  triangles, 
when  one  angle  is  given,  the  diminutions  or  augmentations 
which  one  of  the  two  remaining  angles  may  undergo  are  com- 
pensated by  equal  augmentations  or  diminutions  of  the  other 
remaining  angle ;  and  compensated  in  such  a  way  that  the 
total  magnitude  of  the  two  remaining  angles  is  the  magnitude 
requisite  to  form  with  the  given  angle  a  number  of  angles 
equal  to  two  right  angles. — When  this  is  effected,  our  in- 
quirer has  found  a  fixed  connection  between  the  values  of  the 
second  and  third  angle,  another  fixed  connection  between  the 
sum  of  these  values  and  the  value  of  the  first  angle,  and,  by 
these  two  connections,  he  explains  the  whole  value  of  the 
three  angles.  But  he  has  reached  his  limit,  he  can  go  no 
further.  Besides  this,  after  all  these  measurements,  additions, 
subtractions,  and  recapitulations,  he  has  grounds  of  doubt ; 
he  must  ask  himself  whether  the  triangles  he  has  drawn  are 
absolutely  perfect,  if  the  divisions  of  his  semicircle  are  strictly 
equal,  whether,  in  applying  his  semicircle  to  the  angles,  he 
has  made  the  lines  of  division-  coincide  exactly  with  the  sides 
of  the  angles.  Let  him  use  a  powerful  microscope  ;  he  will 
find  that  in  very  few  cases  are  these  conditions  fulfilled,  and 
he  must  suppose  that,  if  the  microscope  were  more  powerful, 
he  would  not  find  them  fulfilled  in  any  case.  Therefore,  all 


430  THE  KNO  WLEDGE  OF  GENERAL    THINGS.       [BOOK  IV. 

he  can  affirm  is  that,  in  triangles  apparently  perfect,  the  sum 
of  the  three  angles  is  apparently  equal  to  two  right  angles. — 
Now,  let  the  geometrician  come  in  ;  he  draws  one  triangle 
only;  in  fact,  he  does  not  busy  himself  with  this  or  any  other 
figured  triangle  ;  his  object  is  any  triangle  whatever  ;  he  ex- 
pressly tells  us  this;  to  him,  the  apparent  figure  is  but  a 
means  of  more  readily  effecting  a  mental  construction  ;  his 
eyes  follow  on  the  board  or  paper  ideal  lines,  to  which  the 
physical  marks  do  but  approximately  correspond.  He  com- 
pletes his  mental  construction  and  his  apparent  figure,  by 
drawing  through  the  vertex  of  the  triangle  and  parallel  to  the 
base,  on  the  one  hand,  an  ideal  line,  on  the  other,  a  physical 
mark,  so  that  between  this  mark  and  line  there  is  a  rough  cor- 
respondence. Having  completed  his  mental  construction,  he 
resumes  his  definitions  of  the  triangle  and  of  parallel  lines,  he 
observes  their  elements,  he  follows  with  his  finger  these  ele- 
ments in  the  approximating  mark,  he  finds  in  one  or  more  of 
them  the  property  he  is  in  search  of,  and  thus  proves  the  the- 
orem by  the  analysis  of  his  definitions. 

Axioms  are  analogous  theorems,  but  we  dispense  with 
their  proof,  either  because  it  is  very  easy  or  because  it  is  very 
difficult.  In  other  words,  they  are  analytical  propositions,  the 
subject  of  which  contains  the  attribute,  either,  in  a  very  evi- 
dent manner,  which  renders  the  analysis  useless,  or,  in  a  very 
hidden  manner,  which  renders  the  analysis  almost  impracti- 
cable. Hence  there  are  two  kinds  of  axioms,  which  border 
on  one  another  by  transitions. 

At  the  foot  of  the  scale  are  some  which  seem  insignifi- 
cant ;  this  arises  from  the  required  analysis  being  completely 
effected  ;  the  terms  of  the  attribute  are  found  before-hand  in 
the  terms  of  the  subject ;  the  reader  does  not  find  the  propo- 
sition instructive ;  he  says  that  he  has  been  told  the.  same 
thing  twice  over.  Such  are  the  celebrated  metaphysical 
axioms  of  identity  and  contradiction. — The  first  may  be  thus 
expressed :  if,  in  an  object,  there  be  a  certain  datum  present, 
that  datum  is  present. — The  second  may  be  formulated  thus : 
if,  in  an  object,  there  is  a  certain  datum  present,  that  datum 
is  not  absent ;  if,  in  an  object,  there  is  a  certain  datum  absent, 
that  datum  is  not  present. — As  the  words,  present  and  not  ab- 


CHAP.  II.]  GENERAL   JUDGMENTS.  43  r 

sent,  absent  and  not  present  are  synonymous,  it  is  plain  that  in 
the  axiom  of  contradiction  as  well  as  in  the  axiom  of  identity, 
the  second  half  of  the  phrase  repeats  a  portion  of  the  first ;  it 
is  a  repetition  ;  we  have  manoeuvred  without  gaining  ground. — 
Thence  we  get  a  third  metaphysical  axiom,  that  of  the 
alternative,  less  empty  than  the  preceding  ones  ;  for  a  short 
analysis  is  required  to  prove  it ;  we  may  enounce  it  in  these 
terms :  in  every  object,  a  particular  datum  is  either  present 
or  absent. — In  fact,  suppose  the  contrary,  that  is  to  say,  that 
the  datum  may  be  neither  absent  nor  present  in  the  object. 
Not  absent,  means  that  it  is  present ;  not  present,  means  that 
it  is  absent ;  the  two  together  mean,  then,  that  the  datum  is 
at  once  present  and  absent  in  the  object,  which  is  contrary 
to  the  two  branches  of  the  axiom  of  contradiction,  to  the  one 
which  says  that,  if  a  particular  datum  is  present  in  an  object, 
that  datum  is  not  absent,  and  to  the  other  which  says  that 
if  a  particular  datum  is  absent  from  an  object,  that  datum  is 
not  present. — Let  us  now  resume  the  axiom  of  the  alterna- 
tive, and  observe  the  attitude  of  the  mind  which  comes 
across  it  for  the  first  time.  It  is  implied  in  a  heap  of  propo- 
sitions, which  we  explicitly  admit,  because  we  impliedly  admit 
the  axiom.  For  instance,  some  one  tells  us  that  every  triangle 
is  equilateral  or  not ;  every  vertebrate  animal  is  a  quadruped  or 
not.  Without  examining  any  triangle  or  any  animal,  we  nec- 
essarily recognize  that  these  propositions  are  true  ;  the  alterna- 
tive is  inevitable  and  cannot  be  evaded.  And  yet,  in  most 
cases,  we  have  not  the  proof  at  hand.  We  have  not  made  the 
foregoing  analysis ;  we  could  not  show,  as  has  been  shown 
above,  the  series  of  links  by  which  the  proposition  is  reduced 
to  the  axiom  of  contradiction.  We  have  not  disengaged  and 
followed,  as. just  now,  the  very  abstract  ideas  which,  by  their 
delicate  and  continuous  network,  fasten  together  the  two 
elements  of  the  proposition.  What  does  this  mean,  except 
that,  in  the  absence  of  a  clear  view  of  this  consolidation  you 
have  a  confused  sentiment  of  it,  and  that  the  connection  exists 
between  the  two  elements  of  your  thought  without  your  being 
able  to  fix  precisely  on  the  points  of  connection? — We  see 
daily  this  effectiveness  of  latent  ideas  ;  we  feel  that  a  certain 
person  could  not  have  acted  in  a  particular  way,  that  certain 


432  THE  KNOWLEDGE   OF  GENERAL   THINGS.       [BOOK  IV. 

conduct  would  be  inopportune,  that  a  certain  action  is  right 
or  blamable,  and  most  frequently  we  cannot  say  why ;  never- 
theless, there  is  a  why,  a  secret  reason  ;  this  reason  is  an  idea, 
an  idea  included  in  the  total  conception  which  we  have 
formed  of  this  person,  this  conduct,  this  action  ;  it  exists  in 
the  total  conception  like  a  segment  not  marked  out  in  a  circle, 
like  a  grain  of  lead  in  a  pound  of  lead ;  it  is  active  in  the 
conception  just  as  its  associated  elements ;  together  they 
form  a  mass  which,  coming  in  contact  with  another  mass, 
shows  sometimes  an  affinity  resulting  in  union,  sometimes  a 
repugnance  resulting  in  separation.  Later  on,  by  reflection, 
we  disintegrate  this  mass ;  by  means  of  abstract  words,  we 
isolate  its  component  ideas ;  we  find  one  among  them  which 
explains  to  us  the  involuntary  junction  or  insurmountable 
incompatibility  of  our  two  conceptions. — That  there  are  some 
demonstrating  ideas  included  in  the  terms  of  the  preceding 
axiom,  we  cannot  doubt,  since  we  have  just  detected  them  and 
arranged  them  in  proof.  That  undetected  ideas  may  and  must 
act  in  the  latent  state  to  unite  or  sever  two  conceptions  in 
which  they  are  included,  is  certain,  since  we  are  daily  wit- 
nesses of  the  fact.  We  may  conclude,  then,  that  the  mental 
consolidations  and  repulsions  proved  respecting  the  preceding 
axiom,  have  as  their  cause  the  concealed  presence  of  the 
latent  ideas  which  we  just  now  detected,  and  we  may  con- 
jecture that,  in  all  similar  axioms,  it  is  the  same  cause 
which  produces  the  same  effect. 

IV.  It  would  be  too  long,  and  moreover  useless,  to  analyse 
them  all.  Let  us  apply  ourselves  to  those  which  are  the 
most  fruitful,  and  which  serve  for  the  construction  of  whole 
sciences. — At  the  head  of  arithmetic,  algebra,  and  geometry, 
are  inscribed  the  two  following  axioms :  if  equal  magnitudes 
be  added  to  equal  magnitudes,  the  wholes  are  equal ;  if  equal 
magnitudes  be  taken  from  equal  magnitudes,  the  remainders 
are  equal. — No  doubt  we  may  form  these  two  propositions 
by  ordinary  induction,  and,  most  probably,  it  was  in  this 
manner  that  they  were  first  established  in  our  mind.  Take 
two  flocks,  each  of  twenty  sheep,  in  separate  inclosures  ;  they 
may  be  increased  or  diminished  in  number ;  they  are,  then, 
magnitudes.  I  drive  fifteen  sheep  into  the  first  inclosure, 


CHAP.  II.]  GENERAL   JUDGMENTS,  433 

and  fifteen  other  sheep  into  the  second  ;  I  then  count  the 
two  flocks  so  increased,  and  find  that,  in  each  field,  there  are 
thirty-five  sheep.  I  then  take  seventeen  sheep  from  the  first 
inclosure,  and  seventeen  others  from  the  second  ;  I  then  count 
the  two  flocks  so  diminished,  and  find  that,  in  each  field, 
there  are  eighteen  sheep. — As  often  as  I  have  performed 
similar  operations,  under  similar  conditions,  upon  any  number 
of  any  kind  of  animals,  or,  more  generally,  upon  any  collec- 
tion of  any  distinct  objects  or  facts,  I  have  verified  that  the 
result  was  similar.  The  same  observation  is  made  when  the 
collection  is  no  longer  composed  of  natural  individuals,  like  a 
sheep,  a  pebble,  or  of  facts  naturally  distinct,  like  a  sound,  a 
blow,  a  sensation,  but  of  artificial  individuals,  like  a  metre,  a 
litre,  a  gramme,  or  of  facts  artificially  divided,  like  the  suc- 
cessive parts  of  a  continuous  movement.  For  instance,  here 
are  two  vessels  in  each  of  which  are  six  litres  of  water  ;  I 
pour  three  litres  of  water  into  the  first,  and  three  litres  of 
water  into  the  second  ;  I  then  measure  the  two  quantities  of 
water  so  increased,  and  find,  in  each  vessel,  nine  litres  of 
water.  I  then  draw  five  litres  of  water  from  the  first  vessel, 
and  five  litres  from  the  second,  and  find  there  is  left,  in  each 
vessel,  four  litres  of  water. — Each  of  these  cases  is  an  experi- 
ment. A  child  does  the  same  with  marbles ;  if  he  has 
counted  two  large  equal  heaps,  and  adds  to  them  two  little 
heaps  which  he  has  also  counted  and  found  equal,  and  finds, 
on  counting,  that  the  whole  heaps  are  equal,  this  will  be  a 
discovery  for  him,  and  I  imagine  that  he  will  be  as  much 
delighted  at  it  as  a  physicist  who  has  observed  for  the  first 
time  some  unknown  phenomenon. — After  many  similar  ex- 
periments, we  are  able  inductively  to  conclude,  by  the  method 
of  Agreement,  that  equal  magnitudes  added  to  equal  magni- 
tudes give  equal  sums,  and  that  equal  magnitudes  taken  from 
equal  magnitudes  give  equal  remainders.  For  if  sometimes, 
as  in  the  experiment  made  with  vessels  of  water,  the  sums  or 
remainders  are  not  rigorously  equal,  we  may  legitimately 
attribute  this  inequality  to  the  inaccuracy  of  our  preliminary 
measures  or  the  awkwardness  of  our  subsequent  manipulation, 
since  the  more  accurate  our  measures  and  the  more  skilful 
our  manipulation,  the  smaller  does  the  inequality  become. — 
28 


434  THE  KNO  WLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

Besides,  to  strengthen  our  conclusion,  we  have  at  hand 
another  inductive  method,  that  of  Difference.  As  soon  as  we 
suppress  the  equality  of  the  primitive  magnitudes  or  of  the 
added  magnitudes,  the  equality  of  the  obtained  wholes  disap- 
pears. As  soon  as  we  suppress  the  equality  of  the  primitive 
magnitudes,  or  of  the  magnitudes  taken  away,  the  equality  of 
the  subsisting  remainders  disappears.  These  two  first  equali- 
ties, then,  are  the  antecedent  of  the  third,  as  the  third  is  the 
consequent  of  the  two  first ;  and  we  have  a  couple  in  which 
the  two  terms,  obtained  like  cooling  and  dew,  are  connected, 
like  cooling  and  dew,  without  exception  and  without  con- 
dition. 

But  the  two  axioms  thus  formed  may  also  be  formed  in 
another  manner.  In  fact,  let  us  lay  aside  experience,  let  us 
close  our  eyes,  and  shut  ourselves  up  in  the  confines  of  our 
own  mind  ;  let  us  examine  the  terms  which  make  up  our  pro- 
positions ;  let  us  attempt  to  find  out  what  it  is  we  mean  by 
the  words  magnitude  and  equality,  and  let  us  see  what  men- 
tal constructions  we  form,  when  we  fabricate  the  idea  of  a 
magnitude  equal  to  another. — Here  we  must  distinguish  be- 
tween artificial  magnitudes  in  which  the  units  are  natural, 
and  natural  magnitudes  in  which  the  units  are  artificial. 
Let  us  examine  them  in  turn,  and  first  as  to  natural  magni- 
tudes which  we  also  term  collections. 

Take  a  collection  of  similar  individuals,  some  flock  of 
sheep,  or  a  collection  of  abstract  units,  some  mental  group  of 
pure  units,  pictured  to  the  eye  by  the  same  sign  many  times 
repeated.  We  call  these  collections  magnitudes ;  and,  if  W2 
give  them  this  name,  it  is  because,  they  are  capable  of  becom- 
ing greater  or  smaller,  while  retaining  their  nature ;  we  mean 
to  say  by  this  that  we  may,  in  fact  or  by  thought,  add  to  the 
flock  one  or  more  sheep,  add  to  the  group  one  or  more  units, 
take  from  the  flock  one  or  more  sheep,  take  from  the  group 
one  or  more  units.  Let  us  now  compare  one  of  these  collec- 
tions with  another  analogous  collection*  and  make  correspond, 
in  thought  or  otherwise,  a  first  object  of  the  first  with  a  first 
object  of  the  second,  a  second  with  a  second,  and  so  on,  till 


Duhamel,  "  De  la  Methode  dans  les  Sciences  de  Raisonnement,"  i.  3. 


C:  :.-.:•.  II.]  GENERAL  JUDGMENTS.  435 

one  of  the  two  be  exhausted.  Two  cases  present  themselves. 
Either  the  two  collections  are  exhausted  together ;  the  num- 
ber of  sheep  is  then  the  same  in  the  first  and  in  the  second 
flock,  the  number  of  units  is  the  same  in  the  first  and  in  the 
second  group  ;  and  in  this  case  we  say  that  the  two  magni- 
tudes are  equal.  Equality,  then,  means  presence  of  the  same 
number. — Or  one  of  the  two  collections  is  exhausted  before 
the  other;  the  number  of  sheep  is  then  different  in  the  first 
and  second  flock,  the  number  of  units  is  different  in  the  first 
and  second  group  ;  and  in  this  case  we  say  that  the  two  mag- 
nitudes are  unequal.  Inequality,  then,  means  presence  of  two 
different  numbers. 

Now,  for  these  kinds  of  magnitudes,  we  are  able  to  prove 
the  axiom.  Let  there  be  two  equal  magnitudes  to  which  we 
add  equal  magnitudes.  According  to  the  foregoing  analysis, 
this  means  that  the  first  collection  contains  a  certain  number 
of  individuals  or  of  units,  that  a  certain  number  of  them  is 
added  to  it,  that  the  second  contains  the  same  number  of  in- 
dividuals or  of  units  as  the  first,  that  the  same  number  of  them 
is  added  to  it  as  to  the  first,  that,  in  the  two  cases,  the  same 
number  is  added  to  the  same  number,  and  that,  therefore,  the 
two  final  collections  contain  the  same  number  added  to  the 
same  number,  that  is  to  say,  the  same  total  number  of  individ- 
uals or  of  units,  whence  it  follows,  from  the  definition,  that 
the  two  sums  or  final  magnitudes  are  equal  magnitudes. — And 
so  again  let  there  be  two  equal  magnitudes,  from  which  we 
take  two  equal  magnitudes  :  according  to  the  same  analysis, 
this  means  that  the  first  collection  contains  a  certain  number 
of  individuals  or  of  units,  that  a  certain  number  of  them  are 
taken  from  it,  that  the  second  contains  the  same  number  of 
individuals  or  of  units  as  the  first,  that  the  same  number  of 
them  are  taken  from  it  as  from  the  first,  so  that  in  the  two 
cases  the  same  number  is  diminished  by  the  same  number, 
and  that,  therefore,  the  two  final  collections  contain  the  same 
number  diminished  by  the  same  number,  that  is  to  say,  the 
same  remaining  number  of  individuals  or  units  ;  hence  it  inva- 
riably follows,  from  the  definition,  that  the  two  remainders  or 
final  magnitudes  are  equal  magnitudes. 

From  artificial  magnitudes,  let  us  pass  to  natural.     The 


436  THE   KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

most  important  of  these  are  the  geometrical,  since  they  serve 
as  measures  for  all  the  rest :  times,  velocities,  forces,  masses, 
etc.  These  geometrical  magnitudes  are  lines,  surfaces,  solids  ; 
and,  if  we  term  them  magnitudes,  it  is  because  they  may  be- 
come greater  or  less  ;  we  mean  to  say  that,  in  fact  or  mental- 
ly, we  may  add  a  line  to  a  line,  a  surface  to  a  surface,  a  solid 
to  a  solid.  Let  us  now  compare  a  line  with  a  line,  or  a  surface 
with  a  surface,  and  apply,  in  thought  or  otherwise,  the  second 
to  the  first,  taking  care  in  doing  so  not  to  alter  the  second  in 
any  way.  Here,  as  before,  two  cases  present  themselves. — Ei- 
ther the  second  coincides  exactly  and  completely  with  the  first, 
so  as  to  become  absolutely  confounded  with  it ;  in  this  case, 
the  two  lines  form  only  one  and  the  same  line ;  we  then  say 
that  the  two  magnitudes  are  equal.  To  say,  then,  that  two 
magnitudes  are  equal,  is  to  say  that  after  the  application,  in 
other  words,  when  omission  and  abstraction  are  made  of  the 
two  distinct  positions,  the  two  lines,  surfaces,  etc.,  are  the 
same. — Or  else,  the  second  line  does  not  exactly  and  completely 
coincide  with  the  first :  in  which  case  the  two  lines,  not  being 
confounded,  remain  different,  we  then  say  that  the  two  magni- 
tudes are  unequal.  To  say,  then,  that  two  magnitudes  are 
unequal,  is  to  say  that  after  the  application,  in  other  words, 
when  omission  and  abstraction  is  made  of  their  two  distinct 
positions,  the  two  lines,  surfaces,  etc.,  are  different. 

Now  we  can  also  prove  the  axiom  for  these  kinds  of  mag- 
nitudes. Let  there  be  two  equal  magnitudes  added  to  two 
equal  magnitudes.  According  to  the  foregoing  analysis,  this 
means  that  a  certain  primitive  line,  surface,  etc.,  is  given,  that 
a  complementary  one  is  added  to  it,  that  a  second  primitive 
line,  when  its  distinct  position  is  omitted,  is  the  same  as  the 
first  line,  that  to  it  is  added  a  complementary  line,  the  same, 
except  as  to  its  distinct  position,  as  the  other  complementary 
line,  that  in  the  two  cases,  when  abstraction  is  made  of  the 
distinct  positions,  the  same  line  is  added  to  the  same  line,  and 
that,  therefore,  the  two  completed  lines  are  the  same  line 
added  to  the  same  line,  that  is  to  say,  the  same  total  line, 
hence  it  follows,  from  the  definition,  that  the  two  sums  or 
total  magnitudes  are  equal. — And  so  again,  let  two  equal  mag- 
nitudes be  taken  from  two  equal  magnitudes.  According  to 


CHAP.  II.]  GENERAL    JUDGMENTS.  437 

the  same  analysis,  this  means  that  a  certain  primitive  line, 
surface,  etc.,  is  given,  that  a  portion  of  it  is  cut  off,  that  a  sec- 
ond primitive  line  is,  when  its  position  is  omitted,  the  same 
as  the  first,  that  from  it  is  cut  off  a  portion,  which,  except  as 
to  its  distinct  position,  is  the  same  as  the  other  portion  cut  off, 
that,  in  the  two  cases,  when  abstraction  is  made  of  the  dis- 
tinct positions,  the  same  line  is  taken  from  the  same  line,  and 
that,  therefore,  the  two  diminished  lines  are  the  same  line 
diminished  by  the  same  line,  that  is  to  say,  the  same  remaining 
line,  hence,  it  follows,  from  the  definition,  that  the  two  re- 
mainders or  final  magnitudes  are  equal. — We  might  demon- 
strate in  the  same  way  a  third  axiom,  which  is  true  of  nat- 
ural magnitudes  as  well  as  of  artificial,  that  is  to  say,  that  two 
magnitudes  each  of  which  is  equal  to  a  third  magnitude  are 
equal  to  one  another. 

Let  the  reader  take  the  pains  to  examine  the  artifice  of 
this  proof.  By  thought,  and  with  the  auxiliary  confirmation 
of  sensible  facts,  we  make  two  artificial  magnitudes  corre- 
spond, feature  for  feature,  or  we  make  two  natural  magnitudes 
coincide,  element  for  element ;  if  this  correspondence  or  coin 
cidence  are  absolute,  the  idea  of  equality  arises  in  us.  We 
have  watched  its  birth  and  distinguish  its  foundation  ;  it  com- 
prises a  more  simple  element  and  is  reduced  to  the  idea  of 
sameness ;  in  fact,  in  a  certain  aspect,  when  what  it  is  neces- 
sary to  omit  is  omitted,  the  two  magnitudes  become  the  same. 
Consequently,  in  the  inverse  aspect,  when  what  it  is  necessary 
to  add  is  added,  the  same  magnitude  is  transformed  into  two 
equal  magnitudes.  Cut  away  from  the  two  magnitudes  their 
distinctive  characteristics,  from  the  two  equal  artificial  mag- 
nitudes the  property  of  belonging  to  two  distinct  collections, 
from  the  two  equal  natural  magnitudes  the  property  of  having 
distinct  positions  ;  they  become  the  same  magnitude.  Con- 
versely, take  the  same  magnitude  twice  and  attach  it  succes- 
sively to  two  distinct  collections  or  to  two  distinct  positions  ; 
it  will  be  transformed  into  two  equal  magnitudes.  Under  the 
word  equal  dwells  the  word  same ;  here  we  have  the  essential 
word  ;  this  is  the  latent  idea  included  in  the  idea  of  equality 
When  severed  and  followed  through  several  intermediate  prop- 
ositions, it  reduces  the  axiom  to  an  analytical  proposition. 


438  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

By  means  of  it  we  connect  the  attribute  to  the  subject ;  we 
see  the  idea  present  in  both  ;  but,  before  we  saw  it  there,  we 
had  a  presentiment  that  it  was  there  ;  it  was  actually  there, 
and  evidenced  its  presence  by  the  constraint  it  exercised  on 
our  affirmation  ;  though  not  detected,  it  performed  its  office  ; 
We  felt  indeed  that  two  magnitudes  being  equal  might,  by 
that  alone,  be  substituted  for  one  another,  that,  therefore,  the 
aukmentation  or  diminution  undergone  by  the  second  might 
be  substituted  for  the  corresponding  augmentation  or  diminu- 
tion undergone  by  the  first.  We  divined  with  certainty,  but 
without  the  power  of  stating  the  matter  precisely,  that  in  the 
two  data  and  in  the  two  operations,  there  was  something  of 
the  same  ;  the  analysis  has  only  isolated  this  same  thing,  and 
has  shown  us  in  a  distinct  state  the  virtue  it  possessed  in  us 
in  the  latent  state. 

V.  There  are  twelve  axioms  of  this  kind  at  the  commence- 
ment of  Euclid's  geometry ;  many  of  them  are  reduced  to 
preceding  ones  ;  others,  comprising  the  ideas  of  whole,  of 
part,  of  greater,  of  less,  are  easily  demonstrated  from  the  pre- 
liminary definition  of  these  terms.*  The  last  and  more  im- 
portant ones  deserve  to  be  studied  apart  ;  they  are  the  ones 
concerning  the  straight  line  and  parallel  lines.  Let  us  first 
observe  that  the  usual  definition  of  the  straight  line  is  a  bad 
one  ;  we  say  that  it  is  the  shortest  which  can  be  drawn  from 
one  point  to  another.  This  is  not  a  primitive  property,  but 
a  derived  property ;  we  do  not,  in  conceiving  it,  watch  the 
generation  of  the  line  ;  we  do  not  possess  the  elements  of  the 
mental  construction  ;  we  do  but  hold  one  of  its  consequences. 
Besides,  "  this  definitionf  reduces  a  notion  to  others  which 
we  do  not  possess  and  which  are  much  less  simple  than  the 
first.  What  in  fact  do  we  understand  by  a  line  being  less 
short  or  greater  than  another  ?  It  is  that  this  line  is  made 
up  of  a  part  equal  to  the  first  and  of  a  remainder  of  some  kind. 
Now,  two  equal  lines  are  those  which  may  coincide,  and  con- 


*  Read  as  to  this,  Duhamel,  op.  cit.  ii.  3-6. — Equal  angles  are  defined  by  the 
coincidence  of  their  sides  ;  the  perpendicular  by  the  equality  of  the  two  adjacent 
angles  it  makes  ;  the  right  angle  by  the  perpendiculars,  which  form  its  sides. 

f  Duhamel,  op.  cit.  p.  7. 


CHAP.  II.]  GENERAL   JUDGMENTS.  439 

sequently,  equality  cannot  be  conceived  between  two  lines 
whose  figure  does  not  admit  of  superposition,"  which  is  the 
case  with  the  straight  line  referred  to  the  other  indefinitely 
numerous  broken  or  curved  lines  with  which  it  would  be  nec- 
essary to  compare  it  in  order  to  verify  that  it  is  shorter  than 
any  of  them.  This  is  not  the  way  in  which  the  acute  and  sub- 
tle Greek  analysts  have  defined  the  straight  line ;  Euclid  does 
not  admit  at  the  outset  that  it  is  the  shortest  line  between 
two  points  ;  he  proves  it  later  on,  by  comparing  triangles  of 
which  it  forms  a  side,  which  prove  it  to  be  shorter  than  any 
broken  line,  then,  by  extending  the  case  of  the  broken  line  to 
that  of  the  curve  which  forms  its  limit. — We  must  seek  then 
for  another  definition,  and,  according  to  our  custom,  watch 
its  construction.  Now  we  constructed  it  by  considering  two 
given  points,  and  by  observing  the  line  described  by  the  first 
point  when  it  moves  towards  the  second  and  towards  the  sec- 
ond only,  as  opposed  to  the  line  described,  when,  before  mov- 
ing towards  the  second,  it  moves  towards  another  or  several 
other  points,  which  produces  a  broken  line,  or,  towards  an  in- 
finite series  of  other  points,  which  produces  a  curved  line. 
We  thus  see  that,  in  the  straight  line  drawn  from  a  point,  the 
whole  line,  that  is  to  say  the  straight  line  itself,  being  solely 
and  completely  determined  by  its  relation  with  one  second 
point  alone,  all  its  characters,  whatever  they  may  be,  known 
or  unknown,  are  solely  and  completely  derived  from  the  rela- 
tion it  has  with  this  second  point  alone. 

Hence,  two  consequences,  one  relating  to  the  whole  line, 
the  other  relating  to  its  various  parts. — If  we  start  from  the 
same  first  point,  and  trace  another  line  which  also  moves  to- 
wards the  same  second  point,  and  towards  this  only,  this 
second  line  does  but  exactly  repeat  the  first ;  for  all  its  char- 
acters, like  all  those  of  the  first,  are  completely  and  solely 
derived  from  the  relations  which,  like  the  first,  it  has  with 
this  second  point  alone  ;  hence  we  see  that  the  characters  of 
the  two  lines,  whatever  they  may  be,  known  or  unknown,  are  all 
absolutely  the  same,  in  other  words,  that  these  two  lines  are 
confounded  together  and  form  but  one:*  this  we  express  in 


*  An  entirely  analogous  demonstration  shows  that  two  circumferences  whose 
radii  are  equal  become  confounded  into  one  single  one. 


<4O  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

various  ways,  by  saying  that  between  two  points  we  can  only 
draw  one  straight  line,  that  two  points  are  sufficient  to  de- 
termine the  interposed  straight  line,  that  two  straight  lines 
having  two  points  in  common  coincide  in  all  their  interme- 
diate extent,  and  from  this,  we  easily  deduce  that  two  straight 
lines  which  cut  one  another  cannot  enclose  a  space.* — So 
much  for  the  whole  line ;  let  us  now  consider  its  various 
parts.  Since  the  entire  line  described  is  completely  and 
solely  determined  by  its  relation  to  the  second  point  and  de- 
rives thence  all  its  characters,  each  of  its  constituent  portions 
is  solely  and  completely  determined  by  the  same  relation  and 
also  derives  thence  all  its  characters,  excepting  one,  namely 
— the  property  of  being  one  particular  portion  and  not 
another,  situated  at  some  spot  or  other  of  the  line,  at  its 
commencement,  its  middle,  or  its  end.  Consequently,  if  we 
make  abstraction  of  this  particularity,  all  the  portions  of  the 
line  have  exactly  the  same  characters,  in  other  words,  they 
are  the  same.  Let  us  effect  this  abstraction,  and,  for  this, 
suppress  the  particular  position  of  a  fragment  of  the  line,  by 
taking  it  from  the  spot  at  which  it  is,  for  instance  the  end, 
by  transferring  it  elsewhere,  for  instance  to  the  beginning, 
and  there  applying  it  to  the  whole  line.  It  will  be  con- 
founded with  the  portion  on  which  it  is  applied,  and  the  two 
fragments  will  make  one  only.  Hence  it  follows  that  any 
portion  of  the  straight  line,  taken  from  its  position  and  ap- 
plied to  any  other  portion  of  the  whole  line,  will  rigorously 
coincide  with  the  portion  to  which  it  is  applied.f 

When  this  is  settled,  we  know  the  relation  of  any  portion 
whatever  of  the  straight  line  to  any  other  portion  whatever 
of  this  same  line,  and  are  consequently  able  to  follow  it,  be- 
yond the  two  points  through  which  we  have  drawn  it,  up  to 
an  infinite  distance.  In  fact,  take  a  straight  line  A  B,  pro- 
long it  to  any  distance  beyond  the  point 

— — -^     '•     B,  put  in  such  a  way  that  it  remains 

straight,  that  is  to  say    in  accordance 

*  This  last  proposition  is  the  I2th  axiom  of  Euclid. 

\  An  analogous  demonstration  shows  that,  in  the  same  circle  or  in  equal  cir- 
cles, any  arc  transferred  from  its  place,  will  exactly  coincide  with  the  portion  of 
circumference  on  which  it  may  be  placed.  This  arises  from  the  circumference 
ei.i  -,  like  the  straight  lin<*  ?>  ""iform  line. 


CHAP.  II.]  GENERAL   JUDGMENTS.  441 

with  the  preceding  condition,  in  such  a  way  that  any  one  of  its 
portions  may  coincide  with  any  other  of  its  portions,  therefore 
with  all  those  which  are  comprised  in  its  prolongation.  Now, 
suppose  a  second  straight  line  traced  from  A  to  B,  and  also 
prolonged  to  any  distance ;  we  have  already  proved  that  be- 
tween A  and  B  it  will  coincide  with  the  first,  but  we  must 
further  prove  that,  beyond  B,  however  far  we  may  prolong 
it,  it  will  coincide  with  the  prolongation  of  the  first  line.  For, 
let  us  assume  that  at  some  point  or  other  it  ceases  so  to  coin- 
cide, and  that,  on  leaving  the  point  C,  for  instance,  it  diver- 
ges above  or  below  the  first ;  then  let  us  take  a  portion  of 
the  line  drawn  common  to  the  two  lines,  A  B  for  instance, 
and  apply  it  to  the  first  line,  at  the  point  C,  so  that  it  may 
extend  beyond  that  point  in  both  directions.  Since  the  first 
line  is  straight,  this  portion  will  coincide  on  both  sides  of  C  with 
a  fragment  of  the  first  line  to  which  it  has  been  applied.  Since 
the  second  line  is  assumed  to  be  straight,  this  same  portion 
must  also  coincide  on  both  sides  of  C  with  the  fragment  of 
the  second  line  to  which  it  has  been  applied.  But  this  is 
contradictory,  since  beyond  C,  the  second  fragment  diverges 
from  and  ceases  to  coincide  with  the  first.  There  is,  then,  a 
contradiction  in  the  second  line  being  straight  and  ceasing  to 
coincide  with  the  first.  Its  divergence  excludes  its  straight- 
ness,  and  its  straightness  its  divergence.  If  it  has  ceased  to 
coincide  with  the  first,  it  is  from  its  having  ceased  to  be 
straight ;  in  order  for  it  to  remain  straight,  it  must  con- 
tinue to  coincide  with  the  first ;  in  order  for  it  always  to  re- 
main straight,  it  must  always  continue  to  coincide  with  the 
first.  Consequently,  two  straight  lines  which  have  two  points 
in  common  coincide  throughout  all  their  extent,  to  whatever 
distance  they  may  be  prolonged ;  or  again,  two  points  are 
sufficient  completely  to  determine  in  a  straight  line,  not 
merely  the  portion  joining  them,  but  also  the  whole  entire 
line  prolonged  to  any  distance  in  both  directions. 

"  The  definition  and  properties  of  the  straight  line,"  said 
D'Alembert,*  "  are  the  stumbling-block,  and,  so  to  speak,  the 
scandal  of  elementary  geometry."  If  I  am  not  mistaken,  we 

*  Melanges. — Eclaircissements  sur  les  Elements  de  Philosophic,  v.  207. 


442  THE  KNO  WLEDGE  OF  GENERAL  THINGS.      [BOOK  IV 

have  now  seen  that  this  scandal  may  disappear,  and  that  the 
assumed  axioms  are  theorems  capable  of  proof.  According 
to  D'Alembert,  parallel  lines  present  an  analogous  difficulty. 
It  is  rash,  no  doubt,  to  approach  an  obstacle  which  great 
minds  and  specialists  have  pronounced  unsurrnountable  or  un- 
surmounted  ;  but  here,  happily,  it  is  less  a  question  of  discov- 
ering a  demonstration  than  of  analyzing  a  construction  ;  we  are 
doing  the  work  of  psychologists  rather  than  of  geometricians  ; 
we  are  simply  searching  for  the  inner  secret  process  by  which, 
beneath  the  accessory  and  insufficient  testimony  of  the  eyes, 
we  base  the  unshakable  conviction  of  the  mind. — How  do  we 
form  the  notion  of  two  parallel  lines  ?  The  usual  method  is, 
to  erect  a  perpendicular  at  any  point  of  a  straight  line  lying 
in  a  plane,  and  another  perpendicular  at  another  point ;  these 
two  perpendiculars  are  said  to  be  parallel  to  one  another.* — 
Now,  what  is  there  primitive  in  this  construction  ?  Nothing, 
except  that  we  suppose  two  straight  lines,  each  of  them  per- 
pendicular to  a  third  line,  denoting  by  the  name  perpendicu- 
lar the  straight  line  which,  standing  on  another  straight  line, 
makes  the  adjacent  angles  equal  to  one  another ;  it  is  from 
this  construction  that  all  the  properties  of  parallels  must  be 
deduced. — Now,  what  are  these  properties?  We  perceive 
that,  in  these  two  perpendiculars  compared  to  one  another, 
there  is  something  the  same ;  in  fact,  each  of  them  forms  with 
the  base  the  two  same  right  angles  ;  and,  in  consequence,  one 
of  the  two  with  its  angles,  applied  to  the  other,  will  coincide 
completely  with  the  other  and  its  angles.  They  are,  then,  ex- 
cept in  one  circumstance  alone — their  position  at  two  different 
points  of  the  base — the  same ;  and  this  partial  identity,  pro- 
vided we  know  how  to  follow  it,  must  be  manifested  by  pre- 
cise consequences. — Let  us  conceive  the  whole  portion  of  the 
base  intercepted  by  their  feet  to  mount,  with  uniform  motion, 
remaining  rigid  and  in  such  a  way  that  one  of  its  elements 
traces,  in  rising,  a  perpendicular  to  the  base.  Since  it  is  a 
straight  line,  all  its  elements  are  similar ;  except  in  their  dis- 
tinct position,  they  are,  as  we  have  seen,  the  same  element : 


*  D'Alembert  proposes  another  construction,  very  analogous,  but  somewhat 
less  simple. — Op.  cit.,  p.  202. 


CHAP.  II.]  GENERAL   JUDGMENTS.  443 

hence,  it  follows  that,  in  their  common  ascent,  they  will  all  of 
them  trace  similar  straight  lines — that  is  to  say,  the  same  with 
the  exception  of  their  distinct  position  ;  hence,  it  finally  fol- 
lows that,  as  one  of  these  lines  is  perpendicular,  all  the  rest 
will  be.  This  is  why,  if  the  extremity  A  traces 
a  perpendicular  in  its  ascent,  the  extremity  B 
will  trace  another,  and  the  line  A  B  will,  in  its 
ascent,  have  traced  two  perpendiculars  at  A  and 
B.  But  since  it  is  always  the  same  line  A  B  A  B 

which  ascends,  it  will  be  everywhere  the  same  at  all  points  of 
its  course,  and  as  it  is  this  line  which  measures  the  distance 
of  the  two  perpendiculars,  this  distance  will  always  be  the 
same  at  all  points  of  the  course.  Hence  it  follows  that  the 
distance  of  the  two  perpendiculars  invariably  remains  the 
same,  and  has  as  its  measure  the  portion  of  the  base  inter- 
cepted by  their  feet  ;  hence  it  follows,  a  fortiori,  that  the  two 
perpendiculars,  having  a  distance  invariably  between  them, 
will  never  meet. 

This  is,  in  my  opinion,  the  secret  mental  operation  which 
sustains  and  clears  up  the  evidence  of  our  senses,  when  we 
prove,  or  imagine  that  we  prove,  by  the  eye  that  the  two  per- 
pendiculars will  always  maintain  the  same  distance  from  one 
another.  We  have  better  reason  for  admitting  this,  than  the 
approximately  equal  durations  of  the  sensations  experienced 
through  our  ocular  muscles.  We  have  no  need  to  apply  re- 
peatedly the  same  measure  to  one  of  the  perpendiculars,  to 
note  with  a  pencil  the  distance  indicated  by  the  first  measure- 
ment, to  compare  it  with  those  indicated  by  subsequent 
measurements,  and  to  verify,  by  recapitulation,  that  all  the 
measurements  agree  in  indicating  equal  distances.  The 
mind  admits  this  equality  on  the  spot,  but  because  it  has  it- 
self created  the  equality,  it  creates  the  equality  by  causing 
the  same  intact  line  to  ascend,  and  also  to  descend  ;  it  is  vaguely 
conscious  that,  at  the  commencement  and  conclusion  of  its 
construction,  this  line  is  the  same  ;  this  is  the  silent  reminis- 
cence which  is  added  to  the  suggestion  of  the  eye  and  antici- 
pates the  verifications  of  the  measure,  to  render  useless  the 
employment  of  the  measure,  and  to  confirm,  by  stronger  evi- 
dence, the  insufficient  testimony  of  the  eye. 


444  THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

Such  is  not  the  case  with  the  second  principal  proposition 
relating  to  parallel  lines,  and  which  is  termed  Euclid's 
postulate.  It  is  in  fact  a  postulate,  and  not  an  axiom.  It 

consists  in  saying  that,  if  a  line 
M  B  cuts  obliquely  the  first  par- 
allel D  N,  it  will  also  meet  the 
second  parallel  O  C. — We  have  no 
difficulty  in  seeing  the  necessary 
and  sufficient  condition  of  this 
meeting.  It  is  necessary  and  suf- 
ficient for  the  cutting  line  when 
N  prolonged  beyond  B  to  become  suf- 


ficiently distant  from  the  first  parallel  for  a  perpendicular  N  O, 
erected  from  its  meeting  to  a  point  N,  to  be  equal  to  A  B  the  dis- 
tances of  the  two  parallels.  Will  the  line  cutting  the  first  paral- 
lel become  sufficiently  distant  from  it  for  this  ? — We  have  no 
difficulty  in  showing  that  its  distance  increases  in  proportion 
as  it  is  prolonged  ;  for  if,  at  any  moment,  this  distance  were  to 
diminish  or  to  cease  to  increase,  any  two  subsequent  points 
taken  upon  the  line  would  be  at  an  equal  distance  from  the  first 
parallel  line,  and,  as  two  points  are  sufficient  to  determine  a 
straight  line,  the  cutting  line  would  be  confounded  with  a  third 
parallel  passing  through  these  two  points,  which  is  impossible, 
since,  by  the  previous  proposition,  two  parallels  cannot  meet, 
and  since,  by  hypothesis,  our  oblique  line  meets  the  first  par- 
allel. In  proportion,  then,  as  the  cutting  line  is  prolonged,  it 
becomes  more  distant  from  the  first  parallel,  and  the  perpen- 
dicular which  measures  this  distance  is  a  continually  increas- 
ing magnitude. — But  our  question  still  subsists.  Will  this  in- 
creasing magnitude  ever,  in  fact,  increase  sufficiently  to  equal 
a  very  great  magnitude,  and  especially,  any  magnitude  of  any 
extent  we  please,  as  the  distance  of  the  two  chosen  parallels 
may  be  ?  Reduced  to  these  precise  terms,  the  proposition 
leaves  us  in  a  certain  hesitation  ;  no  doubt,  at  first  sight,  see- 
ing an  oblique  line  sensibly  inclined,  and  two  parallels  moder- 
ately distant,  we  decided  that  the  oblique  line,  having  met 
the  first,  would  meet  the  second  ;  the  point  of  junction  was 
at  no  great  distance  ;  we  could  perceive  it  with  our  eyes,  or 
note  it  beforehand  by  imagination  ;  on  these  indications,  we 


CHAP.  II.]  GENERAL   JUDGMENTS.  445 

have  inductively  concluded  with  a  show  of  truth  that,  how- 
ever small  may  be  the  degree  of  inclination,  and  however 
great  the  distance,  the  proposition  will  invariably  be  true.   But, 
if  we  suppose  the  distance  equal  to  the  line  which  joins  a  fixed 
star  to  the  earth,  and  the  inclination  simultaneously  reduced 
to  the  hundred  millionth  part  of  a  second,  our  eyes  no  longer 
avail  us,  our  imagination  fails,  and  we  are  disturbed.    We  be- 
come still  more  so,  if  we  recollect  that  we  may  further  in- 
crease the  distance  and  diminish  the  inclination  beyond  these 
enormous  figures,  and  so  on  indefinitely.     We  become  still 
more  unsettled  when  we  observe  that  certain  magnitudes  in- 
crease indefinitely,  without  ever  being  able  to  attain  a  certain 
limit,  that  however  enlarged  and  swollen,  they  invariably  re- 
main below  a  given  magnitude,  that  the  series  l-f-^-f-i+J-f-re 
etc.,  always  remains  less  than  2,  and  that  perhaps  our  perpen- 
dicular is  in  the  same  position. — We  must  employ  a  more  del- 
icate analysis.     Let  us  attempt  it.     We  have  here  no  diffi- 
culty in  observing  that  the  point  N  becomes  distant  from  the 
point  B  in  proportion  to  the  diminution  of  the  angle  made  the 
oblique  line  with  the  first  parallel.     We  further  observe  that, 
the  angle  remaining  the  same,  the  point  N  becomes  distant 
from  the  point  B  in  proportion  to  the  increase  in  the  distance 
of  the  parallels  ;  then,  combining  these  observations,  we  con- 
clude that  B  N  is  a  magnitude  whose  variations  depend  on  the 
variations  of  two  other  magnitudes.     It  would  be  necessary 
to  give  precision  to  this  double  dependence,  and  for  this  pur- 
pose to  seek  a  fixed  relation,  not  between  the  three  magni- 
tudes, but  between  their  parts,  elements,  or  fractions.     In 
other  words,  it  would  be  necessary  to  find  in  what  proportion 
B  N  would  be  increased  by  halving  the  angle,  and  then,  in 
what  proportion  B  N  would  be  increased  by  doubling  the  dis- 
tance of  the  parallels,  and  consequently,  in  what  compound 
proportion  the  halving  the  angle  and  simultaneous  doubling 
the  distance  would  together  increase  B  N.     If  we  could  de- 
termine exactly  this  relation,  not  only  should  we  be  able  to 
affirm  that,  the  angle  being  diminished  as  much  as  we  please,  • 
and  the  distance  increased  as  much  as  we  please,  the  oblique 
line  would  always  meet  the  second  parallel ;  but  more  than 
this,  when  given  the  angle  and  the  distance,  we  should  be 


446  THE  KNO  WLEDGE  OF  GENERAL   THINGS.      [BOOK  IV- 

able  to  say  what  would  be  the  length  of  B  N,  and  conse- 
quently, to  mark  on  the  second  parallel  the  precise  point  at 
which  the  oblique  line  would  meet  it. — Unfortunately,  the 
trigonometrical  formulae  which  lead  us  to  this  are  themselves 
founded  on  the  supposition  that  the  oblique  line  meets  the 
second  parallel.  We  are  unable,  then,  to  avail  ourselves  of 
them,  and  Euclid's  postulate  remains  a  postulate,  that  is  to 
say  a  proposition  which  we  are  willing  to  admit  by  tolerance, 
but  which  we  are  not  forcibly  compelled  to  give  our  adhe- 
sion to,  and  it  is  the  opinion  of  the  greatest  authorities  among 
geometricians,  that  the  various  demonstrations  which  have 
been  attempted,  though  sufficient  to  induce  our  assent,  have 
not  the  analytical  rigor  appertaining  to  theorems  and  to  axi- 
oms strictly  so  called. 

VI.  The  reader  now  sees  how  axioms  are  formed.  Not 
only  is  the  experience  of  the  eyes  or  imagination  an  indi- 
cation only,  but  moreover,  this  indication  may,  in  certain 
cases,  fail ;  just  now  we  were  unable,  either  with  the  exter- 
nal or  internal  eye,  to  follow  the  prolongation  of  the  two 
parallel  lines  beyond  a  certain  distance  ;  so  again,  we  may 
cite  a  figure  such  as  the  regular  myriagon,  which  we  have 
never  seen  drawn,  which  we  cannot  draw  in  imagination,  and 
as  to  which  we  can,  nevertheless,  form  certain  definite  judg- 
ments. Beneath  the  process  of  the  external  or  internal  eye, 
there  is  a  silent  mental  process,  the  repeated  or  continuous 
recognition  of  a  circumstance  which,  supposed  in  the  primi- 
tive construction,  persists  or  reappears,  always  the  same,  at 
the  various  successive  moments  of  our  operation.  When, 
after  having  erected  my  two  perpendiculars  on  a  base,  I  fol- 
low them  indefinitely  in  imagination  without  being  able  to 
admit  that  at  some  point  or  other  of  their  course  they  ap- 
proach one  another,  it  is  because,  involuntary  and  unawares, 
I  carry  with  them  the  portion  of  base  intercepted  by  their 
feet,  and  because,  at  every  moment  of  the  transit,  this  base, 
which  is  always  the  same  in  my  mind,  makes  itself  vaguely 
recognized  by  my  mind  as  being  always  the  same. — But 
though  reason  may  be  the  real  fabricator  of  the  final  convic- 
tion, the  indication  furnished  by  the  senses  is  of  great  value. 
For  the  testimonies  of  the  eye  and  the  imagination  antici- 


CHAP.  II.]  GENERAL  JUDGMENTS.  447 

pate  and  confirm  the  conclusions  of  the  analysis  ;  we  are  led 
to  the  axiom  by  a  preliminary  suggestion,  and  we  are  main- 
tained in  it  by  a  subsequent  verification.  The  sensible  evi- 
dence serves  as  introduction  and  complement  to  the  logical 
evidence,  and  it  is  by  means  of  this  agreement  that  arithme- 
tic, geometry,  and  even  algebra,  having  immediately  found 
their  axioms,  were  of  such  early  growth. — This  was  not  the 
case  with  mechanics.  In  this  science,  the  axioms  do  not 
concur  with  the  inductions  of  experience ;  at  least,  they  do 
not  concur  with  the  inductions  of  ordinary  experience.  For 
instance,  axioms  tel'l  us  that  matter  is  inert,  incapable  of 
spontaneously  modifying  its  state,  of  passing  from  rest  to 
motion  when  it  is  at  rest,  and  from  motion  to  rest  when  it  is 
in  motion.  Now,  we  are  daily  seeing  bodies  passing  from 
motion  to  rest  or  from  rest  to  motion,  and  as  it  seems,  spon- 
taneously, and  without  the  appreciable  intervention  of  a  new 
condition.  A  projected  stone,  an  oscillating  pendulum,  finally 
stop,  and  we  are  tempted  to  believe  that  they  stop  of  them- 
selves ;  a  mixture  explodes,  an  apple  falls  from  the  tree, 
without  our  senses  detecting  the  new  circumstance  which  has 
been  added  to  the  former  state  and  has  thus  produced  the 
new.  Throughout  the  whole  of  antiquity  and  of  the  middle 
ages,  philosophers  recognized  tendencies  to  rest  or  motion, 
various  in  various  bodies,  the  tendency  downwards  in  the 
falling  stone,  the  tendency  upwards  in  air  and  fire  which  rise, 
the  tendency  to  perfect  circular  movement  in  the  revolving 
stars,  the  abhorrence  of  a  vacuum,  etc.  It  was  at  the  Ren- 
aissance only,  with  Stevinus  and  Galileo,  that  mechanics  com- 
menced ;  and,  most  probably,  the  cause  of  this  long  delay 
was  the  disagreement  of  ordinary  induction  and  of  pure 
reason.  In  place  of  leading  us  to  the  axiom,  experience 
turned  us  from  it ;  instead  of  confirming  it,  experience  denied 
it.  We  had  no  assistance  in  forming  it,  and  if  we  could 
have  formed  it,  observation,  as  then  practised,  would  have 
been  sufficient  to  upset  it.  We  have  ended  by  forming  it, 
and  experience,  better  directed,  is  now  found  to  be  in  ac- 
cordance with  it.  Further  than  this,  it  has  been  so  well  di- 
rected, and,  in  certain  cases,  as  that  of  Borda's  pendulum,  is 
found  so  conclusive  that,  according  to  many  authors,  indue- 


448  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

tion  is  the  only  real  proof  of  the  axiom  ;  they  look  on  the 
principles  of  mechanics  as  propositions  analogous  to  the 
principle  of  attraction,  established  like  it  by  pure  induction, 
limited  like  it  by  the  small  circle  and  small  duration  of  the 
world  our  observation  can  attain,  incapable  like  it  of  being 
applied  beyond  this  except  by  conjecture,  and,  like  it,  simply 
probable,  when  our  rashness  wishes  to  extend  their  empire 
over  all  portions  of  space,  or  to  all  moments  of  time. 

For  ourselves,  we  are  inclined  to  think,  with  Leibnitz  and 
D'Alembert,  that  among  the  principles  of  mechanics,  are 
many  which  are  not  merely  truths  of  experience,  but  also 
analytical  propositions.  In  order  to  show  this,  let  us  closely 
examine  our  constructions. — Take  a  movable  body  moving 
uniformly  in  a  straight  line  for  as  short  a  time  as  we  please, 
and  traversing  as  short  a  space  as  we  please ;  this  is  what  we 
may  term  its  initial,  or  primitive  movement ;  will  it  continue 
to  move,  and,  if  so,  what  will  be  its  movement  ? — However 
short  may  be  the  time  first  elapsed,  for  instance,  the  millionth 
part  of  a  second,  and  however  small  may  be  the  space  first 
traversed,  for  instance,  the  thousandth  part  of  a  millimetre, 
we  can  consider  successively  two  halves  in  this  time  and  two 
halves  in  this  space.  As,  according  to  our  supposition,  the 
movement  has  been  rectilinear,  the  second  two-thousandth  of 
a  millimetre  described  will  be  in  a  straight  line  with  the  first. 
As,  according  to  our  supposition,  the  movement  has  been 
uniform,  the  space  traversed  in  the  second  two-millionth  part 
of  a  second  is  the  same  in  magnitude  with  that  traversed  in 
the  first.  Hence  two  consequences  follow.  Neither  the  di- 
rection nor  the  velocity  of  the  body  have  been  changed.  The 
direction  it  had  during  the  first  fraction  of  space  has  remained 
the  same  during  the  second.  The  velocity  it  had  during  the  first 
fraction  of  time  has  remained  the  same  during  the  second. 
Whether  the  fraction  be  the  second  or  first,  matters  not ;  the 
character  which  forms  their  difference  has  had  no  influence  on 
the  movement ;  as  regards  the  movement,  this  character  has 
been  indifferent  and,  if  I  may  venture  to  say  so,  null. — But, 
among  the  similar  fractions  of  ulterior  space  and  consecutive 
duration,  we  may  conceive  one  immediately  following  our 
second  fraction,  after  the  second  two-thousandth  of  a  milli- 


CHAP.  II.]  GENERAL  JUDGMENTS.  449 

metre  of  traversed  space,  a  third  one,  after  the  second  two- 
millionth  of  a  second  of  time  employed,  a  third  one.  This 
third,  taken  in  itself  and  compared  with  the  second,  differs 
from  it  only  as  the  second  differs  from  the  first ;  it  comes 
after  the  second  as  the  second  comes  after  the  first ;  nothing 
more.  Hence  it  follows  that,  since  the  character  by  which 
the  second  differs  from  the  first,  that  is  to  say  the  property 
of  corning  after  it,  has  had  no  influence  on  the  movement, 
the  character  by  which  the  third  differs  from  the  second, 
that  is  to  say  the  property  of  coming  after  it,  will  have  no 
influence  on  the  movement ;  as  regards  the  movement,  this 
character  will  also  be  indifferent  and  null,  and,  as  during  the 
second  moment  the  body  continued  its  uniform  and  rectili- 
near movement,  so  during  the  third  moment,  without  the 
introduction  of  a  new  influential  character,  it  will  continue 
its  uniform  and  rectilinear  movement.  The  same  reasoning 
will  apply  to  the  fourth,  the  fifth,  and  succeeding  moments, 
and  so  on  to  infinity. 

Reduced  to  these  terms,  the  proof  is  rigorous.  It  is 
wholly  founded  on  two  observations  :  one  being  that  two 
equal  and  contiguous  portions  of  space,  like  two  equal  and 
successive  portions  of  time,  are  exactly  the  same,  excepting 
this  difference,  that  the  second  is  after  the  first ;  the  other 
being  that,  if  this  difference  has  not,  in  one  instance,  had  any 
effect  upon  the  movement,  this  same  difference  will  not,  in  a 
second  instance,  have  any  effect  upon  the  movement,  on 
condition  that,  in  the  second  instance,  it  is  absolutely  the 
same,  and  that  no  other  new  and  influential  difference  has 
intervened.  For  this  we  provide,  by  assuming  that  the  third 
fraction  of  time  and  space  repeats  the  second  absolutely  and 
in  all  respects ;  that,  no  disturbing  character  being  met  with 
in  the  second,  no  disturbing  character  will  be  met  with  in 
the  third  ;  that  in  the  third  space  and  third  instant,  as  in 
the  second  space  and  second  instant,  no  foreign  and  influen- 
tial character  has  been  added  to  arrest,  alter,  hasten,  or  re'- 
tard  the  movement ;  that,  the  little  space  first  traversed 
being  empty,  the  infinite  space  remaining  to  be  traversed  is 
also  empty ;  that,  the  short  duration  first  elapsed  having 
presented  no  modifying  event,  the  infinite  duration  which 
29 


450  THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BooK  IV. 

remains  to  elapse  will  not  present  one.  In  short,  we  con- 
clude from  a  place  to  a  different  place,  and  from  an  instant 
to  a  different  instant,  with  authority  and  certainty,  when 
this  difference,  having  manifested  its  absolute  want  of  influ- 
ence, may  be  considered  as  null  with  reference  to  the  move- 
ment, and  when,  every  other  influential  difference  being  ex- 
cluded by  hypothesis,  the  two  places  and  two  instants  be- 
come rigorously  the  same  with  reference  to  the  movement. 

The  reader  sees  without  difficulty  that  an  analogous  and 
still  more  simple  reasoning  applies  to  the  case  of  a  body  at 
rest ;  for  we  have  not  then  to  take  account  of  space,  but 
simply  of  time. — Let  a  body  be  at  rest  during  a  time  as  short 
as  we  please ;  as  this  time  is  divisible  into  two  halves,  we 
shall  demonstrate  as  before  that,  the  body  having  remained 
during  the  second  half  in  the  same  state  as  during  the  first, 
the  character  by  which  the  second  half  differs  from  the  first, 
that  is  to  say  the  property  it  has  of  coming  after  it,  has  had 
no  influence  on  this  state ;  hence  it  follows  that  a  third  equal 
fragment,  cut  off  from  consecutive  duration,  will  not  have 
any  influence,  unless  there  be  made  to  intervene  some  new 
influential  circumstance,  some  foreign  effective  event.  This 
is  why  the  primitive  rest  will  be  maintained,  so  long  as  this 
exclusion  is  maintained,  and  however  short  may  be  the  initial 
state,  the  body  at  rest,  as  well  as  the  body  impressed  with  a 
uniform  rectilinear  motion,  will  tend  to  persevere  indefinitely 
in  that  state. 

Observe  the  restricted  range  of  the  axiom,  when  thus  de- 
monstrated and  understood.  It  does  not  in  any  way  establish 
that  a  body  impinged  on  by  another  will  assume  a  uniform 
rectilinear  movement,  nor  that  a  body  impressed  with  a  uni- 
form rectilinear  movement  may  lose  it  under  the  force  of  an 
impact,  and  will  then  remain  indefinitely  at  rest ;  these  truths 
are  matters  of  induction  and  experience.  We  are  elsewhere, 
in  the  pure  region  of  abstract  truths ;  we  no  longer  know 
whether,  in  fact,  there  be  any  movable  bodies  at  rest  or  in 
motion ;  we  do  but  extract  and  follow  out  the  consequences 
included  in  an  initial  supposition  or  construction. — This  is  why 
simple  analysis  has  been  so  far  sufficient  and  will  also  be  suffi- 
cient to  demonstrate  two  other  capital  propositions  of  median- 


CHAP.  II.]  GENERAL   JUDGMENTS.  45! 

ics.  Take  an  inflexible  straight  line  A  B  ;  sup- 
pose it  to  move  altogether  and  in  such  a  way 
as  always  to  remain  parallel  to  its  first  posi- 
tion ;  after  a  certain  time  it  becomes  A'  B'  par- 
allel to  A  B,  and  we  assume  this  time  to  be  a 
second.  Now  suppose  that,  during  this  move- 
ment of  the  whole  line,  a  movable  point,  sit- 
uated at  A,  is  itself  directed  in  a  straight  line 
towards  the  point  B,  in  such  a  way  as  to  traverse,  also  in  a 
second,  that  is  to  say  in  the  same  lapse  of  time,  the  straight 
line  A  B.  We  thus  assume  for  A  two  simultaneous  and  dif- 
ferent movements,  the  one  common  to  it  with  the  other 
points  of  the  line  A  B,  the  other  special  to  itself. — Observe 
that  we  do  not  know  if  things  happen  thus  in  nature.  There 
is  nothing  to  prove  that  our  mental  combination  has,  or  even 
can  have,  its  counterpart  in  real  combinations.  We  might  im- 
agine a  state  of  things  in  which,  from  the  very  fact  of  a  body 
moving  in  one  direction,  it  would  be  impossible  for  a  portion 
of  that  body  to  move  at  the  same  time  in  another  direction. 
But  we  have  not  here  to  trouble  ourselves  with  what  the  laws 
of  real  things  permit  or  deny  ;  we  suppose,  in  our  movable 
body,  the  independence  of  two  simultaneous  movements 
taking  place  in  opposite  directions,  reserving  a  verification 
later  on  by  experience  as  to  whether  the  facts  do  or  do  not 
adjust  themselves  to  this  conception. — From  our  two  hypoth- 
eses, what  follows?  By  the  first  it  is  admitted  that  the 
straight  line  A  B,  mounting  towards  A'  B',  becomes,  at  the  end 
of  a  second,  A'  B',  and  that  thus,  at  the  end  of  a  second,  the 
point  B  arrives  at  the  point  B'.  By  the  second,  it  is  admitted 
that  the  movable  point  situated  at  A  is  transferred  from  A 
to  B,  also  in  a  second,  without  the  ascent  of  A  B  interfering 
in  any  way  with  this  movement  of  translation.  This  ascen- 
sion, then,  is  indifferent  and  mill  with  respect  to  the  transla- 
tion, and  the  movable  point  travels  along  A  B  in  motion,  as 
it  would  along  A  B  at  rest.  Hence  it  follows  that,  at  the  end 
of  a  second,  it  has  arrived  at  the  extremity  of  A  B  in  motion, 
just  as  it  would  have  arrived,  at  the  end  of  a  second,  at  the 
extremity  of  A  B  at  rest.  But,  at  the  end  of  a  second,  the 
extremity  of  A  B  in  motion  is  B7 ;  therefore,  at  the  end  of  a 


452  THE  KNOWLEDGE  OF  GENERAL  THINGS.       [BOOK  IV. 

second,  the  movable  point  is  at  B;.  Hence  we  see  that  having 
started  from  the  angle  of  the  parallelogram  it  has  reached  the 
opposite  angle. 

We  have  now  to  enquire  what  line  it  has  described  in  this 
transit.  Two  cases  may  present  themselves,  that  of  uniform 
motion,  and  that  of  motion  which  is  not  uniform.  We  shall 
only  examine  the  first,  the  simplest  of  all :  in  this  case,  the 
velocity  of  A  B  has  remained  the  same  throughout  all  its  as- 
cent, as  also  the  velocity  of  the  movable  point  A  throughout 
all  its  translation.  Consequently,  at  the  end  of  half  a  second, 
A  B  is  found  to  be  exactly  in  the  middle  of 
its  whole  transit,  that  is  to  say  at  C  D,  and 
at  the  end  of  the  same  half  second,  the  mov 
able  point  A  is  found  to  be  exactly  in  the 
middle  of  its  whole  transit,  that  is  to  say  at 
S.  But  as  A  B  has  mounted  in  the  mean- 
time  to  C  D,  the  point  S  belonging  to  it  has 
mounted  with  it,  and  is  to  be  found  at  S',  the 
middle  point  of  C  D,  as  S  is  the  middle  point  of  A  B.  Very 
simple  geometrical  considerations  show  that  this  point  S'  is 
on  the  diagonal,  that  is  to  say  on  the  straight  line  joining  A 
and  B'.  By  subdividing  the  divisions  of  the  second,  we  should 
prove  in  the  same  way  that  all  the  other  successive  positions 
of  the  movable  point  are  likewise  on  the  diagonal,  hence  it 
follows  that  the  line  it  describes  in  its  whole  double  move- 
ment of  ascension  and  translation  is  the  diagonal. — Hence,  a 
very  important  consequence  :  our  movable  body  which  would 
have  described  the  line  A  B  in  a  second,  and  the  line  A  A 
also  in  a  second,  likewise  describes  in  a  second  the  diagonal 
A  B'.  Since,  then,  the  times  employed  are  the  same,  and  the 
spaces  traversed  are  different,  the  velocity  of  the  compound 
movement  will  not  be  the  same  as  the  velocities  of  the  com- 
ponent movements,  it  will  be.  represented  by  the  diagonal,  and 
they  will  be  represented  by  the  two  sides  of  the  angle,  these 
three  lines  being  the  measure  of  the  spaces  traversed  in  the 
unit  of  time.  Now,  we  have  measured  force  by  the  greater 
or  less  velocity  it  impresses  on  the  same  movable  body. 
Suppose  now  two  forces  applied  to  the  preceding  movable 
body,  one  which,,  if  acting  alone,  would  make  it  traverse  the 


CHAP.  II.]  GENERAL    JUDGMENTS. 

line  A  B  in  a  second,  the  other  which,  if  acting  alone,  would 
make  it  traverse  the  line  A  A',  also  in  a  second  ;  apply  them 
both  together  to  the  movable  body  ;  we  have  just  seen  that 
it  will  traverse  the  diagonal  in  a  second.  Hence  it  follows  that 
the  resulting  force,  estimated  by  the  impressed  velocity,  is  to 
the  component  forces,  estimated  also  by  the  impressed  veloc- 
ity, as  the  diagonal  is  to  the  two  sides  of  the  angle.  There- 
fore the  diagonal  measures  the  resulting  force  with  reference 
to  the  component  forces,  just  as  it  measures  the  compound 
velocity  with  reference  to  the  component  velocities. — It  is  now 
sufficient  to  insert,  in  the  measurement  of  forces,  the  second 
element  of  force,  mass,  and  we  have  already  shown  how  this 
idea  is  connected  with  the  idea  of  velocity.*  When  we  have 
done  this,  we  possess  all  the  essential  axioms  of  mechanics, 
and  we  have  formed  them,  as  all  other  analytical  propositions 
are  formed,  by  the  simple  analysis  of  the  mental  combination 
in  which  they  were  included  in  a  latent  state. 

VII.  Other  less  fruitful  axioms  are  also  worthy  of  demon- 
stration by  reason  of  their  immense  range,  and  the  prodigious 
power  they  seem  suddenly  to  confer  on  the  human  mind. 
These  are  the  ones  relating,  not  to  particular  times  compared 
with  other  times,  nor  to  particular  spaces  compared  with 
other  spaces,  but  to  the  whole  of  time  and  the  whole  of 
space.  With  reference  to  a  given  moment,  duration  is  in- 
finite in  the  future  and  the  past,  and  we  may  picture  it  by  a 
straight  line  which  starting  from  a  given  point  is  infinite  in 
both  directions.  With  reference  to  a  given  point,  space  is 
infinite,  in  three  dimensions  ;  first,  in  length,  which  we  picture 
by  supposing  a  point  which  moving  in  a  straight  line  gener- 
ates in  two  directions  an  infinite  straight  line ;  then  in 
breadth,  which  we  picture  by  supposing  this  infinite  straight 
line  by  moving  in  a  direction  perpendicular  to  its  own  to 
generate  on  both  sides  an  infinite  surface ;  lastly,  in  depth, 
which  we  picture  by  supposing  this  infinite  surface  by  mov- 
ing in  a  direction  perpendicular  to  itself  to  generate  on  both 
sides  an  infinite  geometrical  solid. — These  are  propositions 
which  we  cannot  prevent  ourselves  from  holding  to  be  true, 


*  Part  ii.,  Book  iv.,  Ch.  i.,  p.  420  ante. 


454  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

and  thereupon  our  imagination  gives  itself  scope ;  we  repre- 
sent to  ourselves  time  and  space  as  two  infinite,  uniform,  in- 
destructible receptacles.  In  the  one  are  included  all  real 
events,  in  the  other,  all  real  bodies.  However  long  may  be 
a  series  of  real  events,  for  instance,  the  sequence  of  changes 
which  have  occurred  since  the  origin  of  our  solar  system, 
however  vast  may  be  a  group  of  real  bodies,  for  instance,  the 
collection  of  all  the  stellar  systems  to  which  our  telescopes 
can  reach,  the  receptacle  extends  still  further ;  however  we 
might  increase  the  series  or  the  group,  it  would  always  ex- 
tend beyond  them,  and  the  reason  is  that  the  receptacle  has 
no  limits.  We  remain  startled,  and  ask  ourselves  by  what 
marvellous  operation  of  the  mind  we  have  been  able  to  dis- 
cover so  marvellous  a  property. — But  our  astonishment  is 
diminished  when  we  observe  that  the  same  property  is  met 
with  in  all  magnitudes,  and  is  at  an  end  when  we  find  that  it 
is  comprised  in  the  definition  of  magnitude. — Take  the  sim- 
plest of  all  magnitudes,  a  collection  of  individuals  or  units,  as 
small  as  we  please,  that  is  to  say  containing  two  units.  To 
construct  it,  I  have  supposed  two  precisely  similar  units,  that 
is  to  say  the  same  unit  repeated ;  I  have  then  added  the 
second  to  the  first,  I  to  i,  supposing  the  second  unit  to  be 
the  same  before  as  after  the  adjunction,  in  other  words,  that 
the  second  I,  when  added,  remains  intact  and  absolutely  such 
as  before.  Since  the  second  I  is  the  same  as  the  first,  I  may, 
when  it  is  alone,  perform  on  it  the  operation  which  I  have  just 
performed  on  the  first,  and  therefore  add  to  it  I.  Since  the 
second  I,  after  its  adjunction  to  the  first,  remains  absolutely 
such  as  it  was  before,  I  may  add  I  to  it  when  it  is  added  to 
the  first,  just  as  I  added  I  to  it  when  it  was  alone.  I  may 
then  add  i  to  I  -f  i,  that  is  to  say  to  2,  just  as  I  have  already 
added  I  to  I.  An  analogous  reasoning  shows  that  we  may 
similarly  add  i  to  3,  then  to  4,  to  5,  to  6,  and  in  general,  to 
any  number  whatever.  Thus  every  adjunction  we  effect 
generates  the  possibility  of  another  similar  adjunction  ;  hence 
it  follows  that  the  series  of  numbers  is  absolutely  infinite. 
There  is  no  number,  however  enormous,  which  may  not  be 
comprised  in  this  series ;  it  is,  as  regards  imaginable  num- 
bers, what  duration  is  with  regard  to  real  or  imaginable 


CHAP.  II.]  GENERAL    JUDGMENTS.  455 

events,  what  space  is  with  regard  to  real  or  imaginable 
bodies,  a  boundless  receptacle  in  which  every  determined  or 
determinable  number  comes  necessarily  to  find  a  place,  some- 
times above,  sometimes  below,  but  always  in  a  precise  spot, 
without  ever  the  number,  swollen  as  enormously  as  we  please, 
ceasing  to  be  contained  by  the  series  like  &'  thing,  enclosed  by 


things  beyond  it.  -^WftA  P V 

So  much  for  collections  which  are  artificial  and  discontin- 
uous magnitudes  ;  the  same  reasonings  applies  to  times,  lines, 
surfaces,  solids,  which  are  natural  and  continuous  magnitudes. 
Take  any  portion  whatever  of  the  straight  line  A  C  ;  the  first 
notions  of  geometry  show  us  that  it  may  be  divided  into  two 
equal  straight  lines,  A  B,  B  C,  the  second  of  which,  if  applied 
to  the  first,  intact  and  without  alteration,  will  coincide  with 
it  exactly ;  therefore,  except  as  to  its  position  following  the 
first,  it  is  the  same  as  the  first,  and  moreover,  by  hypothesis, 
it  is  the  same  as  before  its  translation.  Since  the  second 
line  is  the  same  as  the  first,  I  may,  when  it  coincides  with 
the  first,  perform  on  it  the  same  operation  as  upon  the  first, 
and  therefore  prolong  it,  like  the  first,  by  a  line  equal  to 
itself.  Since  the  second  line  is  the  same,  now  as  before  its 
translation,  I  may  before  translating  it,  that  is  to  say  when 
it  still  prolongs  the  first,  prolong  it,  like  the  first,  by  a  line 
equal  to  itself.  I  may,  then,  prolong  A  B  C  by  C  D  just  as 

I  prolonged  A  B  by  B  C.     An  analogous 

A  B  C  D  E  demonstration  shows  that  we  can  similarly 
prolong  A  B  C  D  by  D  E  and  so  on,  how- 
ever great  may  be  the  line  so  constituted.  Every  prolonga- 
tion we  effect,  then,  generates  the  possibility  of  another 
equal  prolongation,  whence  it  follows  that  the  series  of  pro- 
longations is  absolutely  infinite. — The  reader  readily  per- 
ceives that,  with  the  necessary  changes  of  words,  this  analy- 
sis becomes  equally  applicable  to  surfaces,  solids,  times,  and 
rigorously  demonstrates  the  infinity  of  time  and  space. — All 
the  artifice  of  the  proof  consists  in  observing  two  elements 
of  a  given  magnitude,  and  remarking  that  they  are  the  same 
except  as  to  their  difference  of  position  in  the  magnitude, 
that  this  difference  is  itself  indifferent,  that  is  to  say  of  no 
effect  and  without  any  influence  on  their  nature,  that,  there- 


456  THE  KNOWLEDGE   OF  GENERAL  THINGS.      [BOOK  IV. 

fore,  the  increase  given  to  the  first  element  by  the  second 
may  be  given  to  the  whole  by  a  subsequent  third  element, 
and  in  general,  to  every  other  analogous  whole  by  a  subse- 
quent element.  What  creates  the  infinity  of  the  series,  are 
the  properties  of  its  elements.  So  again,  it  is  by  comparing 
together  the  elements  of  infinite  series  that  we  compare 
together  such  series  themselves.  This  is  the  process  by 
which  I  know  that  the  infinite  series  of  even  numbers  is 
equal  to  the  infinite  series  of  odd  numbers,  and  that  each 
of  them  is  half  of  the  infinite  series  of  numbers.  This  is  the 
process  by  which  I  know  that  the  infinite  surface  comprised 
above  a  straight  line  between  two  perpendiculars  a  metre 
apart,  is  equal  to  the  infinite  surface  comprised  by  the  same 
perpendiculars  when  prolonged  below  the  line,  and  that 
these  two  infinite  surfaces  taken  together  are  two-thirds  of 
the  infinite  surface  comprised  above  the  line  by  two  perpen- 
diculars three  metres  apart.  Thus,  when  we  study  the  ax- 
ioms which  removes  all  limit  from  the  possible  increase  of 
any  magnitude,  and  which  sets  out  this  magnitude  when  in- 
finitely increased,  as  a  permanent  receptacle  in  which  every 
limited  magnitude  of  the  same  kind  must  necessarily  find  its 
place  and  something  beyond  it,  we  find  only,  as  in  the  other 
axioms,  an  analytical  proposition.  It  has  been  sufficient  in 
every  case  for  us  to  examine  attentively  our  mental  construc- 
tion, to  detect  in  it  conditions  which  are  understood,  the 
latent  identity  of  one  datum  and  another,  the  latent  indiffer- 
ence of  a  character  which  seemed  to  separate  the  two  data, 
identities  and  indifferences  which  we  did  not  perceive  at 
first,  since  our  supposition  had  not  expressly  enunciated 
them,  but  which  were  nevertheless  tacitly  included  in  our 
hypothesis,  and  which,  before  they  were  brought  to  light, 
revealed  their  secret  presence  by  the  invincible  inclination 
they  impressed  on  our  belief,  and  by  the  complete  evidence 
with  which  they  enlightened  our  judgment. 

VIII.  We  now  see  how  it  is  that  the  contraries  of  axioms 
and  their  consequences  are  not  only  incredible  but  incon- 
ceivable;  it  arises  from  their  being  contradictory;  in  this 
sense,  axioms  and  their  consequences  are  necessary  truths. 
There  is  no  question  of  greater  importance  in  psychology, 


CHAP.  II.]  GENERAL  JUDGMENTS.  457 

for  no  question  has  more  important  consequences  in  philoso- 
phy. In  fact,  these  kinds  of  propositions  are  the  only  ones 
which  are  applicable,  not  only  to  all  observed  cases,  but  to 
all  cases,  without  possible  exception ;  hence  it  follows  that, 
on  their  value,  depends  the  reach  of  human  knowledge.  But 
their  value  depends  on  their  origin ;  it  is  essential,  then,  to 
know  whence  they  spring,  and  how  they  are  formed.  To 
this,  two  original  and  still  existing  schools  give  two  opposite 
answers.  Let  me  be  understood  to  speak  only  of  doctrines 
which  hold  a  place  on  the  world's  stage,  and  of  philosophers 
who  have  constructed  their  doctrines  without  other  care  than 
that  for  truth. — Of  the  two  principal  answers,  the  first  is  that 
of  Kant.  According  to  him,  these  propositions  are  the  work 
of  an  internal  force,  and  the  effect  of  our  mental  structure.  It 
is  this  structure  which  effects  the  connection  between  the 
two  ideas  of  the  proposition;  if  the  idea  of  straight  line, 
that  is  to  say  of  a  certain  direction,  is  joined  in  my  mind  to 
the  idea  of  the  least  distance,  that  is  to  say  of  a  certain 
magnitude,  it  is  not  because  this  direction  and  this  distance 
are  in  themselves  connected,  it  is  because  my  intelligence  is 
fashioned  in  a  certain  way,  and,  being  so  fashioned,  cannot 
avoid  establishing  a  connection  between  the  two  ideas  which 
it  has  of  this  distance  and  of  this  direction.  In  fact,  the  two 
data  taken  in  themselves  are  of  different  kinds;  there  is  no 
point  of  real  connection  between  them.  Consequently,  the 
invincible  mutual  attachment  which  I  observe  to  exist  be- 
tween them  in  my  mind  finds  its  explanation,  not  in  their 
intrinsic  nature,  but  in  the  mental  medium  into  which  they 
have  been  introduced.  My  mind  has  not  ascertained  their 
connection,  it  has  constructed  it.  We  must  admit,  then, 
that  these  propositions  reveal  to  us  a  necessity  of  our  mind, 
and  not  a  connection  of  things.  In  the  narrow  circle  to 
which  our  experience  is  confined,  we  may,  indeed,  establish 
by  induction,  that  the  corresponding  sensible  data  are  ap- 
proximately connected  ;  but  to  affirm  that  in  every  place  and 
at  every  time  these  abstract  data  are  connected  and  necessarily 
connected,  is  what  is  not  allowed  us  ;  we  have  no  right  to  im- 
pose on  facts  a  connection  which  belongs  only  to  our  ideas, 
nor  to  set  up  an  infirmity  of  the  subject  as  a  law  of  objects. 


458  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

Starting  from  the  opposite  view,  Stuart  Mill  arrives  at  a 
similiar  conclusion.  According  to  him,  these  propositions 
have  as  their  cause  an  external  force,  and  are,  like  other  truths 
of  experience,  the  summed-up  impression  left  on  our  mind 
by  things.  Considering  two  sensible  lines  sensibly  perpen- 
dicular to  a  straight  line,  we  verify  by  an  infinity  of  readily 
effected  measurements  that  they  remain  equally  distant  from 
one  another.  Further,  we  observe  that,  the  more  exactly 
they  are  perpendicular,  the  more  exactly  equal  are  their 
distances.  Hence  it  follows  that,  if  they  were  rigorously 
perpendicular,  their  distances  would  be  rigorously  equal.  From 
the  equality  of  these  distances  on  our  paper,  we  conclude  by 
induction  that,  far  beyond  our  paper  and  at  an  infinite  dis- 
tance, they  would  still  remain  equal.  If  the  contrary  sup- 
position is  inconceivable,  it  is  owing  to  our  imagination  exactly 
repeating  our  vision  while  giving  it  greater  range ;  the  internal 
eye  does  but  add  a  telescope  to  the  external  eye ;  therefore, 
we  cannot  imagine  the  two  perpendiculars  other  than  as 
we  see  them ;  we  cannot,  then,  prolong  them  mentally,  with- 
out representing  them  to  ourselves  as  still  equally  distant. — 
Hence  it  follows  that  the  truths  termed  necessary,  having 
the  same  origin  as  the  truths  of  experience,  are  subject  to 
the  same  restrictions  and  the  same  doubts.  By  the  axiom  as 
to  parallel  lines  just  as  by  the  law  of  the  movement  of  the 
planets,  we  prove  the  constant  association  of  two  data,  which 
are,  in  fact,  constantly  associated  in  nature ;  but  this  associa- 
tion is  not  a  connection,  it  is  merely  a  concurrence.  Taken 
in  themselves  the  two  data  are  nothing  more  than  incidents 
which  coincide ;  there  is  no  internal  necessity  in  them  which 
assembles  them  in  a  necessary  couple.  Perhaps,  beyond  our 
little  world,  they  are  found  disconnected ;  at  all  events,  we 
have  no  right  to  affirm  that  beyond  it  they  are  in  all  places 
and  in  themselves,  connected.  A  mind  constructed  upon 
another  model  than  ours  might  perhaps  readily  conceive 
varying  distances  between  our  two  perpendiculars.  It  may 
be  that,  beyond  the  nebulae  of  Herschel,  none  of  our  laws  are 
true,  and  there  may  even  be  no  law  which  holds  good. — We 
are,  then,  inevitably  driven  back  from  the  infinite ;  our  fac- 
ulties and  our  assertions  can  in  no  way  attain  to  it ;  we  remain 


CHAP.  II.]  GENERAL   JUDGMENTS.  459 

confined  in  a  very  small  circle ;  our  mind  cannot  carry  itself 
beyond  the  range  of  its  experience ;  we  cannot  establish  any 
universal  and  necessary  connection  between  facts ;  perhaps, 
indeed,  no  such  universal  and  necessary  connection  exists. — 
By  following  out  this  idea  to  its  full  extent,  we  should  arrive 
at  the  conception  of  the  universe  of  events  and  beings  as  a 
simple  collection  or  heap.  There  would  be  no  internal  ne- 
cessity for  their  connections  or  existence.  They  would  be 
pure  data,  that  is  to  say,  things  accidentally  existing.  Some- 
times, as  in  our  system,  they  would  be  found  assembled  in 
such  a  way  as  to  bring  about  regular  recurrences ;  sometimes, 
they  would  be  so  assembled  that  nothing  of  the  sort  would 
occur.  Chance  would  be,  as  Democritus  taught,  at  the  foun- 
dation of  all  things.  Laws  themselves  would  be  derived  from 
it,  and  would  only  be  derived  from  it,  in  certain  places.  It 
would  be  with  beings  as  with  recurring  decimals,  which, 
according  to  the  hazard  of  what  may  be  their  two  primitive 
factors,  sometimes  expand  in  regular  periods,  and  sometimes 
not,  and  which  generate  their  successive  ciphers,  sometimes 
according  to  a  law,  sometimes  without  following  any  law. 

Here  are  two  high  conceptions,  and  the  powerful  minds 
which  formed  them  are  worthy  of  all  admiration  and  respect ; 
but  we  must  examine  the  foundation  on  which  they  are 
built,  and,  in  my  opinion,  this  foundation  is  not  solid. — Ac- 
cording to  Kant,  there  is  no  necessary  connection  between 
the  two  data ;  if  there  is  an  invincible  connection  between 
the  two  corresponding  ideas,  its  cause  lies,  not  in  the  struc- 
ture of  the  data,  but  in  the  structure  of  our  mind.  We  rec- 
ognize, with  Kant,  an  invincible  connection  between  the  two 
ideas.  But  between  the  two  data,  which  are  the  objects  of 
these  ideas,  and  to  which  he  refuses  any  intrinsic  connection, 
we  have  discovered  an  intrinsic  connection  ;  for  the  first,  in  a 
latent  manner,  contains  the  second,  from  which  it  follows 
that  the  contents  being  inseparable  from  what  contains  them, 
the  unsurmountable  connection  between  our  ideas  is  indes- 
tructible between  their  objects. — According  to  Stuart  Mill, 
whether  there  be  a  connection  between  the  two  data  or  not, 
we  are  incapable  of  knowing  it ;  for  the  two  data  are  con- 
nected by  induction  alone ;  and  all  induction  can  prove  be- 


460          THE  KNOWLEDGE   OF  GENERAL  THINGS.       [BOOK  IV. 

tween  them  is  that  they  are  constantly  found  together,  that 
is  to  say,  an  association  of  fact.     We  admit,  with  Mill,  that 
at  the  outset  and  in  many  minds  they  are  only  connected  by 
induction ;  but  we  have  proved  that  they  may  also  be  other- 
wise connected.     We  can  represent  two  perpendiculars  upon 
a  straight  line  by  imagination,  but  we  can  also  conceive  them 
by  reason.     We  can  consider  their  sensible  image,  and  also,  in 
addition  to  their  sensible  image,  their  abstract  definition.     We 
can  study  them  ready  constructed  and  generated,  but  we  can 
also  study  them  during  their  construction  and  generation,  in 
their  factors  and  their  elements.     We  can  watch  their  forma- 
tion and  detect  the  ascension  of  the  base  which  generates  them, 
just  as  we  can  watch  the  formation  of  the  cylinder  and  detect 
the  rectangle  by  whose  revolution  it  is  described.     From  this 
construction  we  extract  the  included  properties,  and  thus  form 
by  analysis  the  proposition  we  at  first  formed  by  induction. — 
Thanks  to  this  second  process,  the  range  of  our  mind  is  ex- 
tended infinitely.     We  are  no  longer  capable  only  of  relative 
and  limited  knowledge ;  we  are  also  capable  of  absolute  and 
unlimited  knowledge ;  in  axioms  and  their  consequences  we 
hold  data,  not  only  accompanying  one  another,  but  such  that 
one  includes  the  other.     If,  as  Mill  teaches,  they  only  ac- 
companied one  another,  we  should  be  driven  to  conclude  with 
him  that  this  might  not  always  be  the  case ;  we  should  see 
no  internal  necessity  for  their  junction ;  we  should  simply 
state  it  as  a  fact ;  we  should  say  that  the  two  data  being  iso- 
lated in  their  nature,  circumstances  might  be  found  in  which 
they  would  be  separate ;  we  should  only  affirm  the  truth  of 
axioms  and  their  consequences  relatively  to  our  world  and 
our  mind.     But  since,  on  the  contrary,  the  two  data  are  such 
that  the  first  includes  the  second,  we  establish  by  that  alone 
the  necessity  of  their  junction ;  the  first,  wherever  it  may 
be,  will  involve  the  second,  since  the  second  is  a  part  of  it- 
self, and  since  a  datum  cannot  be  separated  from  itself.    There 
is  no  place  between  the  two  for  a  circumstance  to  intervene 
to  disjoin  them ;  for  they  are  but  one  thing  in  two  aspects. 
Their  connection,  then,  is  absolute  and    universal,  and   the 
propositions  which  concern  them  do  not  permit  of  doubts, 
limits,  conditions,  or  restrictions. — In  truth,   these  proposi- 


CHAP.  II.]  GENERAL  JUDGMENTS,  461 

tions  are  hypothetical ;  all  they  affirm  is  that,  if  the  first 
datum  be  anywhere  met  with,  and  especially  in  nature,  the 
second  datum  cannot  fail  to  be  also  met  with  there,  by  con- 
sequence and  correspondence.  It  remains,  then,  for  us  to 
prove  that  there  are,  in  fact,  equal  magnitudes,  artificial  and 
natural  straight  lines,  lines  perpendicular  to  a  straight  line, 
bodies  motionless  or  moving  for  a  very  short  time  at  least 
uniformly  in  a  straight  line,  movable  bodies  possessed  of 
constant  velocities  in  different  directions,  homogeneous  sub- 
stances exactly  divisible  into  equal  portions,  in  short,  real 
data  conforming  to  our  mental  constructions.  To  show  this, 
it  is  necessary  and  sufficient  for  experience  to  intervene ;  in 
fact,  in  many  cases,  in  astronomy,  optics,  acoustics,  it  ascer- 
tains that  certain  existing  things  present  the  required  charac- 
ters, or  at  least  tend  to  present  them,  and  would  present 
them,  if  we  could  effect  upon  them  the  proper  eliminations. 
In  all  these  cases  the  necessary  propositions  are  applicable, 
and  the  real  data  have  the  intrinsic  connection  which  Kant 
and  Mill  deny  them. — Thence  follow  vast  consequences,  and 
a  view  of  the  foundation  of  nature,  the  essence  of  laws,  and 
the  structure  of  things  opposed  to  those  of  Kant  and  Mill. 


462  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 


CHAPTER  III. 

THE  CONNECTION  OF  GENERAL  CHARACTERS,   OR  THE    EX- 
PLANATORY  REASON    OF   THINGS. 

§  I.  NATURE  OF  THE  EXPLANATORY  INTERMEDIATE. 

I.  WHEN  we  have  ascertained  a  connection  between  two 
data,  possible  or  real,  it  often  happens  that  this  connection  is 
explainable,  and  we  are  then  able,  not  only  to  affirm  that  the 
two  data  are  connected,  but  also  to  say  why  they  are  con- 
nected.    Between  the  two  data  which  form  a  couple,  there  is 
found  another,  an  intermediate  one,  which,  being  connected 
on  the  one  side  with  the  first,  and  on  the  other  side  with  the 
second,  produces  by  its  presence  the  connection  of  the  second 
and  first,  in  such  a  way  that  this  last  connection  is  derived 
and  presupposes,  as  conditions,  the  two  preliminary  connec- 
tions whose  effect  it  is.    In  this  case  we  conceive  the  two  pre- 
liminary connections  by  two  preliminary  propositions  which 
we  term  premises,  and  we  conceive  the  derived  connection  by 
a  derived  proposition  which  we  term  conclusion. — Nothing  can 
be  more  important  than  this  intermediate  datum,  since  it  is 
the  one  which,  by  its  insertion  between  the  two  data,  consol- 
idates them  into  a  couple.     We  must  attempt  to  find  out  in 
what  it  consists,  how  we  discover  it,  where  we  ought  to  search 
for  it.    When  this  is  done,  we  shall  have  no  difficulty  in  com- 
prehending the  formation  of  the  two  premises  into  which  it 
enters,  and  of  the  conclusion  which  results  from  them. 

II.  There  is  a  case  in  which  we  know  all  this,  that  of  in- 
dividual objects  subject  to  known  laws.     For  instance,  Peter 
is  mortal ;  the  two  lines  drawn  on  this  slate  perpendicularly 
to  a  third  line  are  parallel :  here  are  couples  of  data  in  which 
the  first  member  is  not  general,  but  an  individual,  particular, 
determined  object. — Moreover,  these  objects  are  subject  to 


CHAP.  III.]  THE  EXPLANATORY  REASON.  463 

known  laws  ;  we  know  that  all  men,  among  whom  is  Peter, 
are  mortal,  that  all  straight  lines  perpendicular  to  another 
straight  line,  among  which  are  the  lines  on  our  slate,  are  par- 
allel.— Now,  in  this  case,  the  explanatory  intermediate  which 
connects  the  enounced  property  to  the  individual  object  is  the 
first  term  of  a  general  law  :  if  Peter  is  mortal,  it  is  because  he 
is  a  man,  and  because  every  man  is  mortal ;  if  our  two  lines 
are  parallel,  it  is  because  they  are  perpendicular  to  a  third, 
and  because  all  straight  lines  perpendicular  to  a  third  straight 
line  are  parallel.  But  man  is  a  character  included  in  Peter, 
an  extract  from  him,  more  general  than  he  is ;  so  perpendicu- 
lar to  a  third  is  a  character  included  in  our  two  lines,  an  ex- 
tract from  them,  more  general  than  they  are. — Hence  we  see 
that,  in  the  case  of  individual  objects  subject  to  known  laws, 
the  intermediate  which  connects  the  enounced  property  with 
each  object  is  a  character  included  in  it,  more  abstract  and 
more  general  than  it  is,  common  to  it  and  to  other  analogous 
objects,  and  which,  involving  by  its  presence  the  property 
enounced,  draws  this  property  with  it  in  each  of  the  individ- 
uals to  which  it  appertains. 

Let  us  now  inquire  in  what  this  intermediate  consists, 
when  it  is  a  question,  not  of  connecting  a  property  to  an  indi- 
vidual object,  but  of  connecting  a  property  to  a  general  thing. 
In  othet  words,  from  the  explanation  of  facts,  let  us  pass  to 
the  explanation  of  laws,  and,  for  this  purpose,  let  us  examine 
some  of  the  laws  of  which  the  reason  and  the  why  are  now 
discovered. — In  the  seventeenth  century,  after  the  experi- 
ments of  Galileo  and  Pascal,  it  was  known  that  all  terrestrial 
bodies  tend  to  fall  towards  the  earth,  and,  after  Copernicus 
and  Kepler,  it  was  understood  that  the  earth  and  all  the 
other  planets  tend  to  fall  towards  the  sun.  Newton  came  and 
proved  that  the  two  tendencies  are  the  same ;  gravitation  is 
common  to  celestial,  as  well  as  to  terrestrial,  bodies,  and,  more 
generally,  to  all  bodies.  From  that  time  it  was  known  why 
terrestrial  bodies  tend  to  fall  towards  the  earth,  and  why  the 
planets  tend  to  fall  towards  the  sun.  The  weight  of  the  first, 
and  the  centripetal  tendency  of  the  others,  had  as  reason  a 
property  common  to  both  ;  the  two  laws  were  cases  only  of  a 
third  and  more  extensive  law.  From  the  group  of  characters 


464  THE  KNO  WLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

which  constitute  a  terrestrial  body,  Newton  retained  one  only, 
the  property  of  being  a  mass  with  reference  to  another  mass ; 
he  eliminated  the  rest.  From  the  group  of  characters  which 
constitute  a  planet,  he  retained  one  only,  the  property  of  be- 
ing a  mass  with  reference  to  another  mass  ;  here  again  he 
eliminated  the  rest.  He  had,  then,  derived  from  the  two 
groups  a  general  and  abstract  property,  more  general  and 
more  abstract  than  either  of  them,  contained  in  each  of  them 
like  a  part  in  a  total,  like  a  fragment  in  a  whole,  like  an  ele- 
ment in  a  sum.  Instead  of  connecting,  like  his  predecessors, 
weight  to  the  first  whole  group,  and  centripetal  tendency  to 
the  second  whole  group,  he  connected  the  weight  and  the 
centripetal  tendency  to  an  element  found  alike  in  both  of 
them. — By  this  brillaint  example,  we  see  in  what  the  inter- 
mediate datum  furnishing  the  reason  of  a  law  consists.  Given 
the  object  subject  to  the  law,  this  datum  is  one  of  its  charac- 
ters, a  character  comprised  in  the  group  of  characters  which 
constitute  it,  a  character  included  in  it,  more  abstract  and 
more  general  than  it,  in  short,  an  extract  to  be  extracted. — 
Let  us  follow  out  the  series  of  whys,  and  we  shall  see  that  such 
is  indeed  the  nature  and  position  of  the  becauses,  or  alleged 
reasons. — Why  does  this  stone  tend  to  fall  ?  Because  at  the 
surface  of  the  earth  all  stones,  and  more  generally  still  all  sol- 
ids, or  liquids  opposing  any  resistance  to  our  muscles,  tend  to 
fall. — Why  do  all  these  solids  or  liquids  tend  to  fall  ?  Because 
all  masses  at  the  surface  of  the  earth,  whatever  they  may  be, 
solid,  liquid,  or  gaseous,  tend  to  fall. — Why  do  they  tend  to 
fall  ?  Because  not  only  at  the  surface  of  the  earth,  but  still 
further  distant,  as  we  have  proved  in  the  case  of  the  moon,  in 
all  our  solar  system,  as  is  the  case  with  the  planets  and  their 
satellites,  with  comets  and  the  sun,  far  beyond  again,  as  hap- 
pens with  the  double  stars,  every  mass,  as  soon  as  it  is  in  re- 
lation with  another  mass,  tends  to  approach  it. — Why  this 
strange  tendency?  Physicists*  are  at  present  inquiring  if  it 


*  "  L'Unita  delle  forze  fisiche,  saggio  di  Filosofia  Naturale,"  by  Pere  Secchi.— 
M.  Lame  has  examined  and  adopted  an  analogous  hypothesis. — See  the  develop- 
ment of  the  whole  hypothesis  in"  La  Physique  Moderne,"  by  M.  Saigey,  especially 
p.  146. 


CHAP.  III.]  THE  EXPLANATORY  REASON.  465 

cannot  be  reduced  to  a  continuous  impulsion,  to  the  pressure 
exercised  by  an  ether.  If  we  could  succeed  in  proving  that 
this  ether  in  fact  exists,  and  that  the  density  of  its  successive 
layers  about  a  heavy  body  goes  on  increasing  as  the  square  of 
the  line  which  represents  their  distance  from  the  body,  the 
supposition  presented  would  become  a  demonstrated  truth, 
we  should  have  an  additional  because ;  we  should  detect  in  a 
gravitating  body  a  character  still  more  general  and  more  ab- 
stract than  gravitation,  a  property  wholly  mechanical,  that  by 
which  a  body  follows  an  impulsion,  and  receives  a  new  veloc- 
ity at  each  new  impulsion.  Now  this  last  explanatory  char- 
acter would  have  the  same  characteristics  and  the  same  posi- 
tion as  the  rest.  It  would,  then,  like  the  rest,  be  a  portion, 
an  element,  an  extract  from  the  preceding  one,  and  would,  like 
the  rest,  be  found  in  the  preceding  one,  in  which  it  is  included. 
III.  Let  us  now  look  at  those  laws  in  which  the  explana- 
tory intermediate  seems  at  first  sight  of  a  wholly  different 
kind. — Every  vibrating  body  whose  vibrations  are  comprised 
within  certain  known  limits  of  slowness  and  velocity  excites 
in  us  the  sensation  of  sound.  Why  so  ?  Because  its  vibra- 
tions have,  among  other  characters,  the  power  of  being  propa- 
gated through  the  surrounding  medium  up  to  our  acoustic 
nerve  ;  in  fact,  take  from  them  this  property,  which  we  do  by 
the  suppression  of  the  medium  and  by  setting  the  body  in  a 
vacuum,  the  vibrations  continue-,  but,  as  they  cease  to  be  prop- 
agated, the  sensation  is  no  longer  produced.  Thus  the  reason 
which  renders  these  initial  vibrations  actually  sonorous,  is  the 
possiblity  they  have  of  being  propagated,  a  property  included 
in  them  and  more  general  than  they  are,  since  it  is  met  with 
elsewhere,  for  instance,  in  the  vibrations  of  the  luminous 
ether.  Here  again  the  two  data,  antecedent  and  consequent, 
are  connected  through  the  medium  of  a  character  comprised 
in  the  first,  and  it  is  the  first  which  we  must  study  with  all 
its  circumstances  to  extract  from  it  the  element  which  is  the 
reason  of  the  law. — Now,  why  does  the  vibration  of  the  body, 
when  propagated  through  the  medium  up  to  the  acoustic  nerve, 
excite  in  us  the  sensation  of  sound  ?  Because  it  possesses, 
among  other  characters,  the  power  of  propagating  itself  fur- 
ther still,  along  the  acoustic  nerve,  up  to  the  acoustic  centres 
3° 


THE  KNOWLEDGE   OF  GENERAL    THINGS.     {BOOK  IV. 

of  the  brain ;  in  fact,  take  away  this  property,  which  we  find 
effected  when  the  subject  is  deaf,  and  which  we  can  effect  by 
paralysing  the  brain  with  chloroform  ;  the  vibration  will  be 
propagated  as  far  as  the  acoustic  nerves,  or  even  as  far  as  their 
central  termination ;  but,  as  it  does  not  reach  or  does  not 
disturb  the  cerebral  centres,  it  will  not  excite  the  sensation  of 
sound.  Thus  the  reason  which  renders  vibrations  propagated 
up  to  the  acoustic  nerve  actually  sonorous  is  the  possibility 
they  have  of  being  propagated  beyond  it  up  to  the  cerebral 
centres,  a  property  included  in  them,  and  more  general  than 
they  are,  since  it  is  met  with  elsewhere,  particularly  in  the  lu- 
minous vibrations  transmitted  to  the  retina,  and,  in, "general, 
in  all  the  disturbances  which  external  bodies  impress  on  our 
sensory  nerves.  As  before,  the  two  data,  antecedent  and  con- 
sequent, are  connected  through  the  medium  of  a  character 
comprised  in  the  first,  and  it  is  the  first,  I  mean  the  vibration 
already  propagated  up  to  the  nerve,  which  we  must  study  with 
all  its  circumstances,  to  ascertain  in  it  and  detach  from  it  the 
possibility  of  a  further  and  complete  propagation  which  is  the 
reason  of  the  law. 

We  see  that,  in  this  law,  the  intermediate  datum  is  a  char- 
acter of  the  first  datum,  which  is  the  vibration  ;  just  as,  in  the 
preceding  law,  gravitation  is  a  character  of  the  first  datum, 
which  is  the  planet. — In  fact,  between  the  two  cases  there  is 
an  important  difference.  In  the  first,  the  explanatory  charac- 
ter is  one  of  the  least  stable  elements  of  the  antecedent ; 
whether  the  vibration  be  propagated  or  not,  does  not  depend 
on  itself,  but  on  many  superadded  conditions,  sometimes  pres- 
ent, sometimes  absent ;  it  requires  to  meet  with  a  favorable 
medium,  an  uninjured  nerve,  a  healthy  brain  ;  if  these  circum- 
stances are  absent,  it  cannot  be  propagated  ;  it  may,  then* 
exist  without  being  propagated ;  this  will  happen  if  the  sur- 
rounding medium  is  wanting,  or  if  the  nerve  or  cerebral  cen- 
tres are  in  an  abnormal  state.  In  the  second  case,  on  the  con- 
trary, the  explanatory  character  is  one  of  the  most  stable  ele- 
ments of  the  antecedent ;  even  were  the  planet  to,  be  shivered 
into  fragments  and  to  fall  upon  another,  its  fragments  would 
still  tend  towards  the  sun,  and  towards  every  mass  with  which 
they  might  be  in  relation. — But  this  difference  of  the  two 


CHAP.  III.]  THE  EXPLANATORY  REASON.  467 

cases  in  no  way  alters  their  fundamental  resemblance,  and  in 
the  first,  as  in  the  second,  the  explanatory  intermediate,  stable 
or  unstable,  is  a  more  general  character,  comprised  with  others 
in  the  antecedent,  and  which  must  be  looked  for  in  the  group 
in  which  it  occurs,  that  is  to  say  in  the  first  of  the  two  data 
of  the  law. 

IV.  In  the  law  associating  the  sensation  with  the  vibra- 
tion, the  intermediate  is  composed  of  two  successive  interme- 
diates, the  power  of  the  initial  vibration  to  propagate  itself 
up  to  the  nerve,  and  the  power  of  the  propagated  vibration 
to  propagate  itself  up  to  the  brain.  In  other  laws,  the  inter- 
mediate is  equally  multiplex,  but  the  intermediates  of  which 
it  is  composed  are  simultaneous  and  not  successive.*  Besides 
the  cases  in  which  the  reason  is  a  series  of  reasons,  there  are 
cases  in  which  it  is  a  group  of  reasons. — For  instance,  the 
earth  describes  a  particular  orbit  about  the  sun.  Now  the 
reason  which  determines  this  orbit  is  a  sum  of  distinct  reasons, 
one  of  which  is  the  initial  impulsion,  or  tangential  force,  with 
its  quantity  in  the  case  in  question,  another  gravitation  or  the 
centripetal  force,  with  its  quantity  in  the  case  in  question,  and 
the  last,  the  distance  from  the  earth  to  the  sun  at  a  fixed  time 
and  place.  In  these  instances,  if  .we  ask  the  why,  the  answer 
is  a  sum  of  becauses ;  here  especially  there  are  three  united 
reasons,  three  explanatory  characters,  three  intermediate  data, 
each  of  which,  taken  apart,  is  more  general  than  the  total  an- 
tecedent, and  which,  included  in  it,  concur  by  their  assembled 
influences  to  determine  the  curve  in  question. — Hence  an  im- 
portant consequence.  Suppose  a  law  in  which  the  first  datum 
is  a  whole,  a  compound  of  distinct  parts,  an  assemblage  of 
data  separable  in  fact,  or  at  all  events  mentally  separable ;  it 
is  evident  that  the  explanatory  intermediate  will  be,  as  in  the 
preceding  case,  a  sum  of  intermediates  which  we  have  here 
to  seek  out  and  detect,  one  by  one,  in  the  various  separable 
data  of  which  our  first  datum  is  the  whole. 

Such  is  the  case  with  numbers  and  geometrical  com- 
pounds. Every  number,  written  according  to  our  ordinary 
system  of  numeration,  in  which  the  sum  of  the  digits  is  di- 

*  See,  on  all  these  points,  the  fine  chapter  in  Mill's  "  System  of  Logic,"  book 
iii.,  chap,  xii.,  "  Of  the  Explanation  of  Laws  of  Nature." 


468  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV 

visible  by  9,  is  itself  divisible  by  9.  Every  convex  polygon 
contains  a  number  of  angles  which,  together  with  four  right 
angles,  are  equal  to  twice  as  many  right  angles  as  the  figure 
has  sides.  Here  are  two  laws  in  which  the  first  datum  is  a 
sum  of  separable  data ;  in  fact,  the  written  number  is  noth- 
ing more  than  the  sum  of  its  units  of  various  orders,  and  the 
polygon  is  nothing  more  than  the  sum  of  its  parts ;  hence  it 
follows  that  the  explanatory  intermediates  must  be  sought 
for  in  the  units  of  various  orders  which  make  up  the  number, 
and  in  the  parts  which  make  up  the  polygon. — Let  us  first 
observe  the  number ;  the  units  of  various  orders  which  form 
its  elements  are  already  detached,  prepared,  and  presented 
for  analysis,  and,  to  detect  them,  we  have  only  to  consider 
the  digits  representing  them.  Now  it  is  easy  to  see  that  in 
every  number  the  sum  of  the  units  of  the  second,  third, 
fourth  order,  etc.,  is  divisible  by  9,  with  a  remainder  equal  to 
the  digit  representing  it ;  that,  therefore,  the  sum  of  these 
sums  is  divisible  by  9,  with  a  remainder  equal  to  the  sum  of 
the  digits  which  represent  it ;  that  consequently  the  entire 
number  itself  is  divisible  by  9,  with  a  remainder  equal  to  the 
total  sum  of  the  digits  which  represent  it ;  hence  it  follows 
that  if  the  whole  sum  of  the  digits  is  itself  divisible  by  9,  the 
remainder  disappears,  and  the  entire  number,  divided  by  9, 
leaves  no  remainder. — Here  the  explanatory  intermediate  is 
a  character  included  in  all  the  elements  of  the  number,  ex- 
cept the  first,  and  common  to  all  the  units  represented  by 
a  digit  placed  to  the  left  of  the  first ;  this  character  so  re- 
peated compels  every  number  to  be  divisible  by  9,  with  a  re- 
mainder equal  to  the  sum  of  its  digits,  and  consequently, 
renders  it  divisible  by  9,  on  the  single  condition  that  the  sum 
of  its  digits  is  divisible  by  9. 

Let  us  now  take  the  polygon ;  when  it  is  presented  to  us, 
the  portions  of  surface  which  form  its  elements  are  not 
yet  distinct  and  separate ;  we  are  compelled,  then,  to  create 
them,  and  for  this,  to  effect  divisions  and  trace  lines ;  a  con- 
struction must  precede  the  analysis.  We  take  any  point  in 
the  interior  of  the  polygon  ;  from  this  point  we  draw  straight 
lines  to  all  its  angles  ;  we  thus  replace  the  polygon  by  a 
group  of  triangles  whose  number  is  equal  to  that  of  its  sides. 


CHAP.  III.]  THE  EXPLANATORY  REASON.  469 

Now,  in  each  of  these  triangles,  the  two  angles  at  the  base, 
together  with  the  angle  at  the  vertex,  are  equal  to  two  right 
angles ;  therefore,  if  we  take  all  the  triangles,  and  if,  adding 
together  all  the  angles  at  their  bases,  we  further  add  all  the 
angles  at  their  vertices,  we  shall  have  as  many  times  two 
right  angles  as  there  are  triangles,  that  is  to  say  sides  in  the 
polygon.  But  these  angles  at  the  bases  are  precisely  the 
angles  of  the  polygon ;  so  that  the  angles  of  the  polygon,  if 
we  add  to  them  the  angles  at  the  vertices,  are  equal  to  twice 
as  many  right  angles  as  the  polygon  has  sides.  Now  we 
know  independently  that  the  angles  at  the  vertices  are  to- 
gether equal  to  four  right  angles ;  hence  it  follows  that  the 
polygon  contains  a  number  of  angles  which,  together  with 
four  right  angles,  are  equal  to  twice  as  many  right  angles  as 
there  are  sides. — Here  the  explanatory  intermediate  is  a 
character  comprised  in  all  the  elements  of  the  polygon,  that 
is  to  say  common  to  all  the  triangles  of  which  it  is  the  whole  ; 
this  character,  thus  repeated,  compels  every  polygon  to  con- 
tain a  number  of  angles  which,  estimated  in  right  angles  and 
increased  by  a  constant  number  of  right  angles,  is  double  the 
number  of  its  sides. 

But  it  is  not  only  in  arithmetical  and  geometrical  com- 
pounds that  intermediates  of  this  kind  occur.  Take  a  car- 
nivorous animal  like  the  tiger,  or  a  ruminant  animal  like  the 
ox.  A  number  of  precise  laws  connect  each  of  its  organs, 
and  each  fragment  of  each  of  its  organs,  with  the  rest.  The 
naturalist  who  dissects  one  organ,  knows  beforehand  what 
he  will  find  in  the  others ;  from  the  external  appearance,  he 
predicts  the  internal  structure,  and  can  delineate  the  form  of 
the  stomach,  the  brain,  the  heart,  the  skeleton,  before  he 
has  laid  them  bare.  If  he  is  asked  why,  in  this  animal,  a 
particular  portion  constructed  in  a  particular  way  involves 
some  other  portion,  he  can  answer :  his  predecessors,  from 
Galen  to  Cuvier  and  Richard  Owen,  have  discovered  an  ex- 
planatory intermediate  which,  common  to  all  these  very 
various  parts,  is  the  principal  reason  of  their  structure  and 
relations.  This  intermediate  is  the  property  of  being  useful ; 
each  organ  performs  a  function  which  contributes,  with  the 
rest,  to  a  total  effect ;  therefore,  it  is  appropriate  to  its  func- 


470  THE  KNO  WLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

tion ;  therefore,  it  is  determined  by  its  function.  But  this 
function  is  itself  determined  by  the  others  which  contribute 
with  it  to  the  total  effect ;  hence  it  follows  that  the  organs 
determine  one  another  with  a  view  to  a  total  effect.  In 
other  words,  the  organs  reconcile  their  characters  in  such 
a  way  as  to  reconcile  their  functions,  and  they  reconcile 
their  functions  in  such  a  way  as  to  maintain  the  circuit 
of  loss  and  reparation  which  forms  the  life  of  the  individ- 
ual and  the  succession  of  individuals  which  forms  the 
race. — Consequently,  a  particular  kind  of  teeth  involves  a 
particular  kind  of  intestines,  and  conversely.  If  we  find 
an  intestine  fitted  to  digest  flesh  only,  and  raw  flesh,  the 
animal  has  jaws  constructed  to  devour  its  prey,  claws  fit- 
ted to  seize  and  tear  it,  teeth  fitted  to  cut  and  divide  it,  a 
system  of  motor  organs  fitted  to  catch  it,  senses  capable 
of  perceiving  it  at  .a  distance,  the  instinct  to  hide  itself  in 
order  to  surprise  it,  and  a  liking  for  flesh.  "  Hence  follows," 
says  Cuvier,  "  a  certain  form  of  the  condyle  in  order  that  the 
jaws  may  fit  together  like  scissors,  a  certain  volume  in  the 
crotaphyte  muscle,  a  certain  depth  of  the  fossa  which  receives 
it,  a  certain  convexity  of  zygomatic  arcade  through  which  it 
passes,  and  a  host  of  characters  of  the  skeleton,  the  articu- 
lations, and  the  motor  muscles.  .  .  .  The  form  of  the  tooth 
involves  that  of  the  condyle,  that  of  the  omoplate,  that  of  the 
talons,  just  as  the  equation  of  a  curve  involves  all  its  proper- 
ties, and  just  as,  by  taking  each  property  separately  as  the 
base  of  a  particular  equation,  we  should  rediscover  the  ordin- 
ary equation  and  all  the  other  properties,  so  the  talon,  the 
omoplate,  the  condyle,  the  femur,  and  all  the  other  bones, 
taken  separately,  give  the  tooth,  and  are  conversely  given 
by  it." — This  is  so  true  that,  in  the  same  animal,  the  meta- 
morphosis of  one  organ  involves  an  appropriate  metamorpho- 
sis of  the  rest.  The  tadpole,  which  is  not  carnivorous,  re- 
quiring a  very  long  canal  to  digest  its  food,  has  an  intestine 
ten  times  the  length  of  its  body;  when  changed  into  a  car- 
nivorous frog,  its  intestine  is  but  twice  the  length  from  mouth 
to  anus.  The  voracious  larva  of  the  cockchafer  has  an  oeso- 
phagus, a  vast  muscular  stomach,  surrounded  with  three 
crowns  of  little  csecums,  a  small  intestine,  an  enormous  large 


CHAP.  Ill]  THE  EXPLANATORY  REASON.  47! 

intestine  three  times  the  size  of  the  stomach,  and  filling  up 
the  whole  posterior  third  of  the  body :  when  it  has  become 
a  cockchafer  and  more  temperate,  all  that  remains  of  this 
apparatus  is  a  slender  canal  destitute  of  enlargements. — By 
this  discovery  of  the  explanatory  intermediate,  the  face  of 
the  animal  world  is  entirely  changed.  Before,  we  had  de- 
scriptive anatomy  only;  we  knew  that  in  fact  certain  charac- 
ters accompanied  one  another ;  but  we  did  not  know  why 
they  accompanied  one  another.  They  were  then  simply  in 
juxtaposition  ;  they  are  now  necessarily  connected  ;  in  addi- 
tion to  their  constant  concurrence,  as  we  ascertain  their  obliga- 
tory connection.  Every  organ,  and  further,  every  physical  or 
moral  element,  of  the  living  animal,  comprises,  included  in 
itself,  a  property  repeated  in  all  the  others,  that  is  to  say  the 
particularity  of  tending  to  harmonize  with  the  rest,  in  such  a 
way  as  to  concur  with  them  in  a  certain  final  and  total  effect ; 
and  this  common  intermediate  explains  not  merely  a  prodi- 
gious number  of  characters  in  the  animal,  already  enumera- 
ted by  descriptive  anatomy,  but  also  an  infinite  number  of 
other  more  delicate  and  intimate  characters  which  our  scalpels 
and  microscopes  are  too  clumsy  to  have  yet  attained. 

We  may  now  form  an  idea  of  the  intermediate. — Take  a 
law,  or  a  couple  of  data  connected  together.  What  is  their 
link?  Whence  comes  their  consolidation?  What  is  the 
reason,  the  because,  the  interposed  condition,  which  connects 
the  second  to  the  first?  The  reader  has  just  followed  this 
intermediate,  and  finds  it  reappear,  always  alike,  under  its 
different  forms. — Sometimes  it  is  simple,  like  the  force  of 
gravitation,  which  explains  the  fall  of  heavy  bodies. — Some- 
times it  is  multiplex ;  composed  of  many  intermediates. 
Two  cases  then  present  themselves. — Either  the  components 
are  successive — as  is,  with  the  sonorous  vibration,  the  power 
of  propagating  itself  in  the  surrounding  medium,  and  then 
the  power  of  propagating  itself  along  the  nerve  as  far  as  the 
cerebral  centres  ;  or  else  the  components  are  simultaneous — 
as  are  the  characters  which  combine  to  direct  the  earth  in  its 
course  round  the  sun.  Here  again  we  must  make  a  distinc- 
tion.— Sometimes  the  simultaneous  intermediates  are  of  dif- 
ferent kinds ;  as  are,  in  the  preceding  case,  the  tangential 


472          THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

force,  the  centripetal  force,  and  the  given  distance  from  the 
earth  to  the  sun.  Sometimes  the  simultaneous  intermediates 
are  of  the  same  kind,  and  are  reduced  to  the  same  interme- 
diate repeated  in  all  the  elements  of  the  object.  This  last 
case  is  itself  divisible  into  two  branches. — Either  the  elements 
in  which  the  intermediate  is  repeated  are  similar,  like  the 
units  of  the  number,  or  the  triangles  of  the  polygon  ;  or  they 
are  dissimilar,  like  the  organs  of  the  animal. — But  simple  or 
multiplex,  composed  of  successive  or  of  simultaneous  inter- 
mediates, of  different  intermediates,  or  of  the  same  interme- 
diate repeated,  of  the  same  intermediate  repeated  by  similar 
elements,  or  of  the  same  intermediate  repeated  by  dissimilar 
elements,  the  explanatory  intermediate  is  always  shown  to 
us  as  a  character  or  a  sum  of  characters  included  in  the  first 
datum  of  the  couple,  more  general  than  that  datum  when 
they  are  considered  apart,  and  accessible  to  our  grasp,  from 
being  comprised  in  it  and  separable  from  it,  by  our  ordinary 
processes  of  isolation  and  extraction. 

V.  When  once  the  intermediate  is  detected  and  repre- 
sented in  the  mind  by  a  corresponding  idea,  it  effects  within 
us  an  internal  process  which  we  term  demonstration.  Take 
one  of  the  above-mentioned  laws  :  every  planet  tends  to  ap- 
proach a  central  mass  with  which  it  is  in  relation — the  sun. 
This  law  is  a  couple  of  two  data,  one,  which  is  the  planet, 
the  other,  which  is  the  tendency  of  the  planet  to  approach 
the  central  mass,  and  the  intermediate  connecting  them  is  a 
general  datum,  common,  not  only  to  all  the  planets,  but  to 
all  bodies  situated  at  their  surfaces  and  to  an  infinite  number 
of  other  bodies  ;  I  mean  the  property  of  being  a  mass,  every 
mass  having  this  character  that  it  tends  to  approach  the  cen- 
tral mass  with  which  it  is  in  relation.  Let  us  compare  these 
three  data  with  one  another. — The  first,  the  planet,  contains 
the  intermediate,  that  is  to  say  the  property  of  being  a  mass ; 
it  contains  the  intermediate  as  one  of  its  characters  among 
many  others ;  with  relation  to  the  planet,  the  intermediate 
is  an  extract  only.  The  planet,  then,  is  more  complex  than 
the  intermediate,  and  the  intermediate  is  more  abstract,  that 
is  to  say  more  general,  than  the  planet.  On  the  other  hand, 
this  intermediate  contains  the  last  datum,  the  tendency  to 


CHAP.  III.]  THE  EXPLANATORY  REASON. 

approach  the  central  mass ;  it  contains  this  datum  as  one  of 
its  characters,  among  many  others  ;  with  relation  to  the  in- 
termediate, this  datum  is  an  extract  only.     The  intermediate, 
then,  is  more  complex  than  the  last  datum,  and  the  last  da- 
tum is  more  abstract,  that  is  to  say  more  general,  than  the 
intermediate.— Thus  the  first  datum  of  the  law  contains  the 
intermediate,  which  contains  the  second.     In  another  aspect 
the  first  datum  is  more  complex  than  the  intermediate,  which 
is  more  complex  than  the  second.     In  another  aspect  again, 
the  second  datum  is  more  abstract  and  general  than  the  in- 
termediate, which  is  itself  more  abstract  and  more  general 
than  the  first  datum.— Having  settled  this,  let  us  associate 
the  three  data  in  pairs ;  we  shall  have  three  couples  of  data, 
or  laws.     Every  planet  is  a  mass  ;  now  every  mass  tends  to 
approach  the  central  mass  with  which  it  is  in  relation  ;  there- 
fore, every  planet  tends  to  approach  the  central  mass  with 
which  it  is  in  relation,  that  is  to  say,  the  sun.— Of  these 
three  couples,  the  first  associates  the  first  datum  and  the  in- 
termediate; the  second  associates  the  intermediate  and  the 
second  datum  ;  the  third  associates  the  first  datum  and  the 
second,  and  is  found  to  be  the  law  which  required  demon- 
stration.—If  we  conceive  the  three  couples  in  this  order,  we 
have  three  propositions  corresponding  to  them  and  composed 
of  three  ideas,  associated  in  pairs,  as  the  three  laws  are  com- 
posed  of  three   data   associated  in  pairs.      Of  these  three 
ideas,  the  first,  which  is  more  comprehensive  than  the  second, 
contains   the   second,   which    is   more   comprehensive   than 
the  third,  and  which  contains  the  third,  and  the  mind  passes 
from  the  most  comprehensive  to  the  least  comprehensive  by 
means  of  the  third,  which   is  of  medium   comprehension.* 
Of  these  three  propositions,  the  two  first,  being  preliminary, 
are  termed  premises,  and  the   third,  being   consecutive,  is 
termed  conclusion.     The  two  premises  are  composed,  one,  of 
the  first  idea,  the  most  comprehensive  of  all,  associated  to 
the  second,  which  is  of  medium  comprehension  ;  the  other, 
of  the  second  idea,  which  is  of  medium  comprehension,  asso- 

*  In  my  opinion,  it  is  in  this  order,  according  to  comprehension  and  not  ac- 
cording to  extension,  that  the  terms  should  be  arranged.  In  this  way,  reasoning 
becomes  an  analysis,  and  not  a  logical  trick,  like  the  ordinary  syllogism. 


474  THE  KNO  WLEDGE  OF  GENERAL   THINGS.     [BOOK  IV 

ciated  to  the  third,  the  least  comprehensive  of  all ;  and  finally, 
the  conclusion  is  composed  of  the  first  idea  associated  to  the 
third,  that  is  to  say  of  the  most  comprehensive  idea  asso- 
ciated to  the  least  comprehensive.  Three  propositions  of 
this  kind  assembled  in  this  order  constitute  a  syllogism,  and 
the  syllogism,  according  to  the  saying  of  Aristotle,  becomes 
a  scientific  demonstration,  when,  as  in  the  preceding  case, 
the  intermediate  by  which  it  connects  two  data  is  the  ex- 
planatory reasonf  of  their  connection. 

§11. 

I.  Let  us  leave  to  logicians  the  task  of  following  out  in  all 
their  details  the  properties  of  the  syllogism,  and  the  neces- 
sary relations  of  its  propositions  or  terms;  these  are  but  the 
curiosities  of  science ;  the  essential  thing  for  the  mind  is  to 
know  what  are  the  special  characteristics  and  exact  position 
of  the  explanatory  intermediate,  so  as  to  be  able  to  seek  for, 
find,  and  recognize  it.  From  its  nature  and  situation,  as  we 
have  ascertained  them,  we  can  arrange  a  general  method  of 
inquiry.  Let  us  examine  this  method  successively  in  the 
sciences  of  construction  and  in  the  sciences  of  experience. 

Take  a  law  of  arithmetic,  of  algebra,  of  geometry,  or  of 
pure  mechanics  ;  the  proposition  which  expresses  it  is  termed 
a  theorem  ;  and  this  proposition  affirms  that  a  particular 
datum  constructed  by  the  mind — a  number  of  any  kind,  a 
multiplicand,  a  square,  a  square  root,  a  triangle,  a  sphere,  an 
ellipse — comprises  a  particular  property.  It  is  here  a  ques- 
tion of  demonstrating  the  theorem,  that  is  to  say  of  distin- 
guishing in  the  first  datum  an  intermediate  which  comprises 
the  property  enounced. — We  have,  then,  to  decompose  the 
first  datum  so  as  to  extract  from  it  the  intermediate,  and  it 
is  this  decomposition  which,  later  back,  when  dealing  with 
axioms,  we  termed  analysis.  In  the  Sciences  of  Construction, 
it  can  always  be  accomplished  ;  there  is  no  internal  obstacle 
which  prevents  our  detecting  the  intermediate ;  it  is  included 
in  the  first  datum  as  Constructed  by  our  mind.  In  fact,  the 


*  df  alrluv  KOI  irporepuv.  "  Posterior  Analytics,"  book  i.  chaps,  ii.  iv.  vi. 
atria  signifies  not  merely  the  cause,  but  the  because  demanded.  These  second 
Analytics  of  Aristotle  are  very  superior  to  the  first,  and  are  still  worthy  the  at- 
tention of  students  of  special  sciences. 


CHAP.  III.]  THE  EXPLANATORY  REASON.  475 

combination  we  have  fabricated  is  purely  mental ;  it  is  not 
bound  to  correspond  to  a  real  combination.  It  differs  in  this 
from  the  other  mental  combinations  by  which  we  conceive 
real  objects  ;  it  runs  no  risk,  as  they  do,  of  presenting  blanks, 
of  passing  by  any  important  character  included  in  the  real 
object,  of  omitting  the  explanatory  intermediate  which  con- 
nects the  enounced  property  with  the  real  object ;  freed  from 
this  obligation,  it  is  exempt  from  this  risk.  Once  formed,  it 
is  complete,  and  whatever  be  the  ideal  object — number,  square, 
straight  line,  figure,  geometrical  solid,  velocity,  mass,  force — 
if  the  definition  furnished  is  well  constructed,  the  object  is 
entirely  and  exactly  expressed  by  it.*  For,  by  hypothesis, 
there  is  nothing  more  in  the  ideal  object  than  what  we  have 
put  into  it,  and  all  we  have  put  into  it  are  certain  elements 
grouped  in  a  certain  order,  and  expressed,  together  with  their 
order,  by  the  definition.  Now,  if  this  group  has  a  property, 
it  is  through  the  medium  of  some  character  included  in  its 
elements  or  in  their  mode  of  assemblage,  as  expressed  by  the 
definition  ;  hence  it  follows  that  the  explanatory  and  demon- 
strative intermediate  connecting  the  property  to  the  group 
will  be  found  by  analyzing  the  terms  of  the  definition. 

Such  is  in  fact  the  method  employed  in  the  Sciences  of 
Construction.  All  the  theorems  are  demonstrated  by  analy- 
sis, by  the  analysis  of  the  terms  of  the  definitions.  We  have 
already  seen  this  in  those  first  theorems  with  whose  demon- 
stration we  dispense,  and  which  we  term  axioms.  We  have 
defined  equal  magnitudes,  the  straight  line,  parallel  lines, 
velocity,  force,  mass,  and  have  found  that  the  properties  at- 
tributed by  the  axioms  to  each  primitive  compound  are  con- 
nected with  it  through  the  interposition  of  some  latent,  but 
inherent  character,  enclosed  and  concealed  in  its  definition. 

So  it  is  with  the  later  theorems  concerning  more  complex 
compounds.  Here,  too,  the  explanatory  and  demonstrative 
intermediate  is  a  character,  mere  frequently  a  series  of  char- 
acters, included  in  the  definition  of  the  compound. — We  all 
know  how  a  theorem  of  geometry  is  demonstrated,  as  for  in- 
stance, that  which  says  that  the  opposite  sides  of  a  parallelo- 


*  See  part  ii.,  book  iv.,  chap,  i.,  pp.  409  etseq. 


476  THE  KNOWLEDGE  OF  GENERAL    THINGS.       [BOOK  IV. 

gram  are  equal.  We  refer  back  to  the  definition  of  the  paral- 
lelogram and  find  that  it  is  a  four-sided  figure  of  which  the 
opposite  sides  are  parallel.  As  this  double  property  is  includ- 
ed in  the  definition,  we  extract  it  by  analysis,  and  have  the 
first  of  the  intermediates  we  are  in  search  of. — We  analyze 
this,  and  on  referring  back  to  the  properties  of  parallel  lines, 

we  find  that,  if  we  draw  the  diagonal 
A  C,  the  two  angles  B  A  C,  D  A  C, 
are  equal  to  the  two  A  C  D,  B  C  A, 
each  to  each,  being  alternate  angles  ; 
which  gives  us  a  second  intermediate. 
— But,  on  the  'other  hand,  the  diago- 
nal has  formed  triangles  as  well  as  an- 


gles ;  we  then  analyze  this  third  in- 
termediate, and,  on  referring  back  to  the  properties  of  trian- 
gles, we  observe  that  the  two  triangles  are  equal,  as  having  a 
common  side,  the  diagonal,  comprised  between  two  angles 
equal  each  to  each  ;  hence  it  follows  that  A  B  is  equal  to  D 
C,  and  A  D  to  B  C. — Thus,  the  first  intermediate — the  par- 
allelism of  each  couple  of  opposite  sides — is  derived  from  the 
definition  ;  the  second — the  equality  of  the  two  alternate  an- 
gles which  the  diagonal  forms  with  each  couple  of  parallel 
lines — is  derived  from  the  first ;  the  third — the  equality  of  the 
triangles  which  the  diagonal  forms  on  each  side  with  the  par- 
allel lines — is  derived  from  the  second,  and  finally,  the  equal- 
ity of  the  opposite  sides  of  the  parallelogram  is  derived  from 
the  third.  The  definition,  then,  contains  the  first  intermedi- 
ate, which  contains  the  second,  which  contains  the  third, 
which  contains  the  fourth,  which  contains  the  property 
enounced.  This  forms,  as  it  were,  a  series  of  boxes  enclosed 
in  one  another ;  the  largest  is  the  first  definition,  and  the 
smallest  the  last  attribute ;  each  larger  box  encloses  a  smaller 
one,  and  we  cannot  get  at  any  one  box  till  we  have  opened 
in  turn  all  those  enclosing  it. — Observe  the  difficult  part  of 
the  operation.  Each  intermediate  contains  many  characters 
in  addition  to  the  one  which  we  extract  and  which  leads  us 
up  to  the  property  enounced  ;  we  must  not  fall  into  error,  and 
overlook  the  right  one,  to  extract  another.  In  other  words, 
and  to  continue  the  comparison,  every  larger  box  contains,  in 


CHAP.  III.]  THE  EXPLANATORY  REASON.  477 

addition  to  the  smaller  box  in  which  we  shall  at  last  find  the 
property  enounced,  several  other  smaller  boxes  which  it 
would  be  useless  to  open ;  we  must  set  our  hand,  then,  on  the 
right  box,  and  if  there  are,  as  in  the  preceding -case,  five 
boxes  to  open,  we  must  five  times  consecutively  have  the  tact 
to  make  a  proper  choice. — Besides  this,  it  is  common  to  find 
boxes  which  do  not  open  readily,  a  skilful  turn  of  the  key  is 
required  ;  we  have  been  compelled  to  make  a  construction, 
to  add  a  line  to  the  figure,  to  draw  the  diagonal.  And  this 
turn  of  the  key  has,  in  opening  one  lock,  opened  by  corre- 
spondence a  second ;  in  fact,  this  well  chosen  diagonal  has 
not  only  given  the  two*  pairs  of  alternate  internal  angles — it 
has  also  given  two  equal  triangles.  In  this  lies  the  talent  of 
the  geometrician  ;  he  must,  by  a  prompt  instinct,  or  by  numer- 
ous trials,  successively  open,  without  a  mistake,  the  series  of 
useful  boxes,  and  must  find  out  the  appropriate  turn  of  the  key. 
Let  us  now  follow  his  steps :  he  begins  by  constructing 
very  simple  compounds,  the  single  straight  line,  the  straight 
line  cutting  another,  the  straight  line  perpendicular  to  another, 
two  parallel  straight  lines.  According  to  the  process  we 
have  just  seen,  and  through  an  intermediate,  or  arrangement 
of  intermediates  included  in  the  definition  of  the  compound, 
he  connects  with  it  several  properties. — Then,  combining 
together  his  primitive  compounds,  he  constructs  ulterior 
compounds,  triangles,  quadrilaterals,  and  polygons,  by  means 
of  two,  three,  and  more  straight  lines  cutting  each  other  in 
pairs ;  the  circle,  by  a  straight  line  turning  about  one  of  its 
extremities ;  the  plane,  by  a  revolving  perpendicular  which 
while  revolving  remains  perpendicular  to  the  straight  line 
with  the  relation  to  which  it  was  at  first  perpendicular ;  after 
this  polyhedra,  by  planes  terminating  in  polygons ;  the  sphere, 
by  a  semicircle  revolving  about  its  diameter,  etc.  To  these 
new  compounds,  he  connects  new  properties  by  means  of  new 
theorems.  What  intermediates  djoes  he  employ  ? — They  may 
be  recognized  at  a  glance ;  they  are  the  already  demonstrated 
properties  of  the  preceding  compounds.  The  more  complex 
compound  has  simpler  compounds  as  its  factors,  and  the 
properties  of  its  factors,  introduced  into  it  with  those  factors, 
are  the  intermediates  by  which  we  connect  to  it  the  proper- 


478  THE  KNOWLEDGE   OF  GENERAL    THINGS.       [BOOK  IV. 

ties  with  which  it  is  itself  furnished.  Just  now  we  saw  that 
the  properties  of  the  parallelogram  were  attached  to  it  through 
the  properties  of  the  two  pairs  of  parallel  lines  which  form  its 
elements.  We  should  see  in  the  same  way  that  the  properties 
of  the  sphere  are  attached  to  it  through  the  properties  of  the 
revolving  semicircle  which  generates  it,  and,  in  general,  that 
the  properties  of  any  compound  are  attached  to  it  through 
the  properties  of  the  simpler  compounds  which  are  its  factors. 
— In  this  way,  each  new  compound  is  a  larger  box  into  which 
we  put  several  smaller  boxes,  with  all  they  contain.  In  the 
one  we  term  parallelogram,  we  put  two  pairs  of  parallel  lines 
cutting  each  other.  In  the  one  we  term  circle,  we  put  an 
infinite  number  of  equal  straight  lines,  having  one  common 
point.  In  the  one  we  term  sphere,  we  put  an  infinite  number 
of  equal  semicircles  having  a  common  diameter,  and  the 
properties  of  the  large  box  so  constructed  are  attached  to  it 
through  the  properties  of  the  smaller  boxes  which  it  contains 
with  their  contents. — Hence  it  follows  that  the  ultimate  rea- 
son, the  ultimate  because,  the  ultimate  explanatory  and  de- 
monstrative intermediate,  which  connects  a  property  to  any 
geometrical  compound,  recedes  from  box  to  box,  and  from 
containing  to  being  contained,  in  proportion  as  we  pursue  it 
from  the  sphere  to  the  revolving  semicircle,  from  the  revolv- 
ing semicircle  to  the  revolving  line,  from  the  revolving  line 
to  the  simple  line — that  is  to  say,  from  the  compound  to  its 
factors,  from  them  to  their  factors,  and  so  oa,  to  allow  itself 
to  be  seized  at  last  in  the  primitive  factors — that  is  to 
say,  in  the  little  elementary  boxes  in  which  it  is  included. 
Arrived  here,  we  have,  in  hand  the  ultimate  reason  of  the 
geometrical  law.  It  is  given,  in  all  the  sciences  of  construc- 
tion as  in  geometry,  by  the  axioms;  and  the  axioms  give  it, 
because  they  enounce  the  properties  of  the  primitive  factors. 
Let  us  carefully  consider  this  expression ;  the  ultimate 
reason  of  a  law.  The  laws  we  have  discovered  in  the  sciences 
of  construction  are  of  enormous  number,  and  this  number 
increases  daily.  Now  the  ultimate  intermediates  which  ex- 
plain and  demonstrate  them  are  the  properties  of  five  or  six 
primitive  factors,  enounced  by  a  dozen  axioms,  which  are 
themselves,  as  we  have  seen,  cases  or  applications  only  of  the 


CHAP.  III.]  THE  EXPLANATORY  REASON. 

axiom  of  identity.  From  this  single  source,  spread  out  into 
a  dozen  rivulets,  flow  the  innumerable  streams  and  waves  of 
science.  Such  is  the  value  of  the  primitive  factors  or  ele- 
ments, when  they  are  as  simple,  as  abstract,  and  as  general 
as  possible :  from  their  laws  are  derived  the  laws  of  their  less 
general  and  less  abstract  compounds,  and  so  on,  from  stage 
to  stage,  by  a  gradual  descent,  without  ever  a  failure  of  con- 
tinuity, between  stage  and  stage,  from  the  highest  wave  to 
the  lowest  level.  It  is,  then,  to  the  primitive  factors  that  the 
principal  efforts  of  our  method  should  be  directed. — Hence  a 
new  way  of  considering  magnitudes,  and  especially  geometri- 
cal magnitudes.  Take  a  straight  line,  or  curved  lines,  and 
those  principally  among  curves,  which  we  were  unable  in  the 
beginning  to  define  except  by  the  nature  of  the  solid  from 
which  they  are  derived,  as  was  the  case  with  the  sections  of  the 
cone — that  is  to  say  the  ellipse,  parabola,  and  hyperbola,  and 
with  other  still  more  complex  curves.  Each  of  them  has  a 
form,  and,  when  once  the  line  is  drawn,  we  see  this  form  in 
the  concrete.  But  the  line  is  made  up  of  primitive  factors  or 
elements  which  are  its  points,  and  its  form  is  but  a  whole,  the 
whole  of  the  distinct  positions  occupied  by  its  distinct  points. 
Hence  it  follows  that  there  is  a  reason,  a  because,  an  interme- 
diate to  explain  and  demonstrate  all  the  properties  we  can 
ascertain  in  the  line  and  its  form,  and  that  this  intermediate 
is  met  with  in  the  elements  of  the  line  and  of  its  form — that 
is  to  say,  in  the  various  points  possessed  of  distinct  positions 
of  which  the  line  and  form  are  but  the  total. — Now,  how  do 
we  determine  the  position  of  a  point?  Among  other  means, 
there  is  a  very  convenient  one,  which  con- 
sists in  taking  in  a  plane  two  fixed  axes  A 
B,  B  C,  which  cut  one  another  at  a  known 
angle,  in  drawing  to  the  point,  lines  par- 
allel to  these  axes,  and  in  giving  the  lengths 
of  these  parallels.  These  two  lengths,  which 
we  term  co-ordinates,  are  magnitudes  which, 
when  compared  together,  present  a  certain  relation.  Here, 
then,  we  have  the  position  of  the  point  defined  by  the  mu- 
tual relation  of  two  auxiliary  magnitudes. — Instead,  now, 
of  a  single  point,  let  us  suppose  a  continuous  series  of 


480  THE  KNOWLEDGE   OF  GENERAL  THINGS.      [BOOK  IV. 

points — that  is  to  say  a  line,  such  that  this  relation  may  be 
the  same  for  all  its  points ;  the  line  and  its  form  will  be 
wholly  defined,  and  defined  by  a  character  common  to  their 
elements. 

Thus,  to  confine  ourselves  to  the  simplest  examples,  if, 
the  two  axes  being  given,  the  line  in  question  bisects  the 
angle  between  them,  all  the  points  of  the  bisecting  line  have 
this  common  character  that,  for  each  of  them,  one  of  the  two 
co-ordinates  is  equal  to  the  other.  If  the  line  in  question  is 
a  circumference,  and  the  two  axes  are  perpendicular  to  one  an- 
other and  pass  through  the  centre  of  the  circle,  all  the  points 
of  the  circumference  have  this  common  character  that,  for 
each  of  them,  the  sum  of  the  squares  of  the  two  co-ordinates 
is  equal  to  the  square  of  the  radius.  This  constant  relation, 
which  is  everywhere  maintained  through  all  the  pairs  of  co- 
ordinates, gives  rise,  when  ascertained,  to  an  equation ;  for 
the  bisecting  line,  the  first  co-ordinate  x  added  to  the  second 
co-ordinate  y  is  equal  to  2  ;r ;  x  -\-  y  =  2  x;  similarly,  for  the 
circumference  x3  -j-  j"  =  r*. — This  formula  is  what  is  termed 
the  equation  to  the  line ;  there  is  one  for  the  ellipse,  for  the 
parabola,  the  hyperbola,  for  every  curve,  for  every  surface. 
There  is  a  branch  of  geometry  which  makes  an  analysis  in 
this  way  of  a  line  or  a  surface,  and  on  decomposing  it  into 
its  elements,  discovers  in  these  elements  an  algebraical  char- 
acter common  to  them  all;  this  science  is  termed  analytical 
geometry.  From  the  character  expressed  by  the  equation, 
we  derive  all  the  properties  of  the  line ;  in  other  words,  in 
order  to  attach  the  properties  to  the  line,  we  find  an  inter- 
mediate, a  reason,  a  because  included  in  the  equation  which  is 
the  definition  of  the  line. 

We  see  how  important  is  the  consideration  of  the  ele- 
ments ;  in  fact,  it  has  been  necessary  to  gain  a  true  notion  of 
magnitude,  and  to  give  to  mathematics  all  their  scope ;  it  is 
this  study  which,  under  the  name  of  infinitesimal  calculus, 
constitutes  the  higher  portion  of  the  science.  Instead  of 
comparing  two  magnitudes  taken  in  the  mass,  we  compare 
the  infinitely  small  increments  of  the  two  magnitudes,  incre- 
ments which  are  their  component  factors  and  their  primitive 
elements.  "  It  would  be  wrong,"  says  a  philosophical  mathe- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  48 1 

matician,*-"  to  take  this  second  mode  of  expression  for  noth- 
ing more  than  a  conventional  abbreviation,  a  form  of  lan- 
guage, apparently  more  convenient  because,  more  usually 
employed.  It  is,  in  fact,  more  convenient,  but  simply  be- 
cause it  is  the  natural  expression  of  the  mode  of  generation 
or  extinction  of  magnitudes,  which  increase  or  decrease  by  ele- 
ments smaller  than  any  finite  magnitude.  Thus,  when  a  body 
cools,  the  relation  between  the  elementary  variations  of  the 
heat  and  time  is  the  true  reason  of  the  relation  which  is 
established  between  the  variations  of  these  same  magnitudes 
when  they  have  acquired  finite  values.  This  last  relation,  it 
is  true,  is  the  only  one  which  can  fall  directly  under  our  ob- 
servation, and,  when  we  define  the  first  by  the  second  through 
the  intervention  of  the  idea  of  limit,  we  conform  to  the  con- 
ditions of  our  human  logic.  But,  once  in  possession  of  the 
idea  of  the  first  relation,  we  conform  to  the  nature  of  things, 
by  making  it  the  principle  of  explanation  of  the  value  which 
observation  assigns  to  the  second  relation.  This  is  why  the 
notation  of  infinitesimal  quantities,  imagined  by  Leibnitz, 
constitutes  an  invention  of  capital  importance  which  has  mar- 
vellously increased  the  power  of  mathematics  as  an  instru- 
ment, and  the  field  of  its  applications  to  natural  philosophy." 
In  all  directions,  the  same  conclusion  springs  up.  In  the 
sciences  of  construction,,  every  theorem  which  enounces  a  law 
is  an  analytical  proposition.  Of  the  two  data  whose  connec- 
tion forms  the  law,  the  second  is  connected  with  the  first,  ob- 
scurely or  clearly,  directly  or  indirectly,  by  a  third  datum,  rea- 
son,  explanatory  and  demonstrative  intermediate,  which  is 
contained  in  the  first  datum,  and  itself  contains  a  series  of  sub- 
sequent intermediates  enclosed  in  one  another.  Finally,  if  we 
inquire  into  the  ultimate  reason  of  the  law,  the  ultimate  inter- 
mediate, the  ultimate  because,  after  which  every  question  is  at 
an  end,  because  the  supreme  explanation  is  furnished  and  the 
demonstration  complete,  we  find  that  it  is  a  character  included 
in  the  definition  of  the  factors  or  primitive  elements  of  which 
the  first  datum  is  but  the  collection  and  the  total. 


*  Coumot,  "  Traite  de  I'Enchainement  des  Idees  P\>ndamentales,"  i.  87,  and 
«'  Traite  Elementaire  du  Calcul  Infinitesimal,"  i.  82. — "  In  this  respect  we  may 
truly  affirm  that  infinitely  small  quantities  exist  in  nature." 

31 


482  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

II.  We  come  now  to  the  sciences  of  experience.  Here 
the  resources  are  fewer  and  the  difficulties  greater. — Let  us 
take  one  of  the  laws  examined  above — namely,  that  cooling 
produces  dew,  that  is  to  say  the  liquefaction  and  deposition 
of  the  watery  vapor  in  the  surrounding  air. — Of  the  two 
data,  cooling  and  liquefaction,  whose  couple  forms  the  law, 
the  first,  according  to  the  theory  expounded,  must  comprise 
an  explanatory  character  by  whose  intervention  it  is  con- 
nected to  the  second.  It  is  necessary,  then,  to  decompose  it 
in  order  to  derive  from  it  this  intermediate. — But  I  am  un- 
able to  effect  this  decomposition ;  the  analysis  which  had 
entire  grasp  of  mental  combinations  has  not  an  equal  grasp 
of  real  combinations.  Having  constructed  the  first,  I  know 
all  they  contain,  since,  by  supposition,  they  contain  nothing 
but  what  I  have  put  in  them.  Not  having  constructed  the 
second,  I  do  not  know  all  they  contain,  and  to  the  portion 
of  knowledge  I  possess,  I  must  add  by  further  discoveries  the 
various  portions  I  do  not  possess. — What  is  this  cooling  of 
watery  vapor?  At  the  time  I  establish  the  law  by  induc- 
tion, I  am  ignorant  of  this.  All  I  know  of  it  is,  that  it  is  a 
change  of  state,  occurring  in  the  vapor,  which  excites  in  me 
the  sensation  of  cold.  This  change  is  in  itself  unknown  to 
me;  all  I  know  of  it  is  one  of  its  effects,  and  this  I  only  know 
through  a  sign.  We  have  now,  with  the  aid  of  this  sign  and 
other  indications,  such  as  the  variations  of  the  thermometer, 
to  study  this  change,  to  ascertain  its  intrinsic  properties,  and, 
for  this  purpose,  again  to  employ  induction. — Now,  we  dis- 
cover by  induction  that  cold  applied  to  a  body  in  whatever 
state,  gaseous,  liquid,  or  solid,  tends  to  bring  its  molecules 
mutually  together,  and  in  fact  does  always  bring  them  to- 
gether, except  in  some  exceptional  cases,  in  which  the  ten- 
dency is  neutralized  by  certain  contrary  tendencies  which  the 
bringing  together  may  sometimes  develop.*  Here  is  a  first 
explanatory  intermediate,  included  in  the  characters  of  the 
chilled  body  and  set  apart  by  induction. — Now  other  induc- 
tions establish  that  a  solid,  liquid,  or  gaseous  body  is  a 
system  of  molecules  placed  apart  and  possessed  of  attracting 

*  For  instance,  the   maximum   of  density,  or   of  the  bringing   together   the 
molecules  of  water,  is  found  at    *  4  degrees  (centigrade),  and  not  below. 


CHAP.  III.]  THE  EXPLANATORY  REASON,  483 

and  repelling  forces  in   relation  to  each  other ;  that  in  pro- 
portion to  their  mutual  proximity,  the  mutual  proportions 
of  the  attracting  and  repelling  forces  are  changed  and  re- 
versed ;   that,  during  a  first  period — the  gaseous  state — the 
attracting  forces  may  be  considered  as  annulled  by  the  enor- 
mous amount  of  the  repelling  forces,  which  explains  the  force 
of  tension  in  vapors  and  gases  ;  that  at  the  end  of  this  period, 
when  the  molecules  are  sufficiently  proximate,  there  comes 
an  epoch  of  equilibrium  between  the  attracting  and  repelling 
forces,  an  epoch  differing  according  to  the  different  constitu- 
tion of  the  different  bodies  ;  that,  during  this  stage,  repulsion 
and  attraction  being  almost  neutralized  by  one  another,  the 
molecules  which  have  neither  mutual  attraction  nor  repulsion 
suffer  themselves  to  be  readily  disjoined,  put  forth  no  effort 
against  what  contains  them,  group  themselves  in  a  surface 
parallel  to  the  horizon ;  in  short,  are  fluid  and  present  the 
sensible  characters  which  constitute  the  liquid  state,  instead 
of  the  sensible  characters  which  constitute  the  gaseous  state; 
that  later  on,  beyond  this  second  period,  when  the  molecules 
are  again  brought  still  closer,  an  epoch  is  presented  in  which 
the  attracting  forces  have  not  only  equality  but  marked  as- 
cendancy, an  epoch  differing  according  to  the  different  con- 
stitution of  the  different  bodies  ;  that,  during  this  third  stage, 
the  grouped  molecules  offer  a  more  or  less  energetic  resis- 
tance to  forces  attempting  to  detach  them  from  the  system, 
and,  instead  of  the  sensible  characters  which  constitute  the 
liquid  state,  present  the  sensible  characters  which  constitute 
the  solid  state.      Hence  it  follows  that  when  a  certain  period 
is  passed,  the  gas,  whose  molecules  are  brought  sufficiently  to- 
gether, must  become  liquid,  and  the  watery  vapor  must  become 
water.     Now  we  know  independently  by  induction  the  limit 
at  which  this  period  comes  to  an  end  in  the  case  of  watery 
vapor;  it  is  a  particular  degree  of  the  thermometer  for  a  par- 
ticular quantity  of  watery  vapor  suspended  in  the  air.     Here 
is  the  second  intermediate  required. — If  the  cooling  produces 
liquefaction    of  the  surrounding  vapor,  this  arises  from  its 
bringing  the  molecules  of  vapor  together  beyond  a  certain 
limit ;    if,  beyond  this  limit,  the   approximating  molecules 
arrive  at  the  liquid  state,  this  is  because,  when  this  limit  is 


484          THE   KNOWLEDGE   OF  GENERAL    THINGS.        [BooK  TV. 

passed,  the  excess  of  the  repelling  over  the  attracting  forces 
ceases  without  being  turned  in  the  contrary  direction,  and  in 
consequence  of  this  equilibrium,  the  molecules  cease  to  have 
any  noticeable  mutual  adherence  or  repulsion,  which  is  pre- 
cisely the  liquid  state.  Approximation  of  molecules,  equilib- 
rium between  the  attracting  and  repelling  forces  of  the  mole- 
cules after  a  certain  degree  of  approximation — these  are 
the  two  intermediates  by  which  the  first  datum  of  our  law — 
cooling,  is  attached  to  the  second — liquefaction,  and  the  ap- 
proximation is  a  property  of  the  molecules  of  the  chilled 
vapor.  Equilibrium  is  a  property  of  these  molecules  when 
brought  sufficiently  close.  And  finally,  the  liquid  state  as 
our  senses  perceive  it,  is  a  property  of  the  equilibrium  so 
attained. 

Thus  the  first  datum  of  the  law  contains  among  its  char- 
ractcrs  the  first  explanatory  intermediate,  which  contains  the 
second,  which  contains  the  second  datum  of  the  law.  Plainly, 
this  enclosure  is  similar  to  that  which  we  have  already  ob- 
served in  the  demonstration  of  the  theorems. — No  doubt, 
we  have  not  here  obtained  the  intermediates  by  the  same 
method  as  before.  It  has  not  been  sufficient  for  us  to  con- 
sult our  conception  of  a  cooling  body ;  there  were  too  many 
gaps  in  it ;  it  taught  us  nothing  except  that  the  body  which  ex- 
cites a  sensation  of  cold  in  ourselves  and  a  lowering  of  the  mer- 
cury in  the  thermometer  undergoes  an  unknown  alteration. 
Experiments  and  an  induction  were  required  to  discover  this 
alteration,  which  consists  in  an  approximation  of  molecules. 
And  so,  it  was  not  enough  for  us  to  consult  our  conception 
of  a  body  whose  molecules  approximate ;  here  again  there 
were  too  many  gaps,  it  taught  us  nothing  as  to  the  effects  of 
approximation.  The  great  induction  of  Newton  was  required 
to  enable  us  to  recognize  that  the  attraction  of  the  molecules 
increases  in  the  inverse  ratio  of  the  squares  of  their  distances, 
whence  it  follows  that,  when  a  certain  degree  of  proximity  is 
passed,  the  attracting  forces  must  form  equilibrium  with  the 
repelling  forces  ;  and  the  inductions  of  other  physicists  were 
necessary  to  ascertain  what  degree  of  cooling  induces  this 
degree  of  proximity  between  the  molecules  of  watery  vapor. 
—But,  if  the  processes  of  discovery  have  been  different,  the 


CHAP.  Ill,]  THE  EXPLANATORY  REASON.  485 

structure  of  things  has  been  shown  to  be  the  same.  In  the 
experimental  law  as  in. the  mathematical  theorem,  the  first 
datum  is  a  large  box  which,  through  a  series  of  gradually 
diminishing  boxes,  encloses  as  its  final  contents  the  second 
datum.  Only,  in  the  experimental  law  it  is  not  sufficient,  as 
in  the  mathematical  theorem,  to  set  the  hand  each  time  on 
the  proper  box  and  to  open  it ;  we  do  not  find  the  box  at 
hand,  in  the  mind  ;  we  must  go  els. where,  beyond  the  mind, 
and  seize  it  where  it  is,  that  is  to  say  in  nature,  and  derive  it 
thence  with  a  great  array  of  experiments  and  inductions. 
When  this  is  effected,  we  transfer  it  into  the  mind,  we  fix  it 
there  in  its  place  in  the  box  from  which  it  was  missing,  and 
when,  by  these  excursions,  we  have  thus  procured  all  the 
necessary  boxes,  we  have  only  to  open  them  in  their  order,  to 
pass  uninterruptedly,  as  in  a  theorem,  from  the  first  to  the 
second  datum  of  the  law. 

Let  us  now  consider  those  of  the  experimental  sciences 
which  are  in  a  very  advanced  state,  applied  mechanics, 
physical  astronomy,  optics,  acoustics,  in  which  many  of  these 
boxes  have  been  discovered  and  enclosed.  Between  the  real 
compounds,  of  which  these  sciences  treat,  and  the  ideal  com- 
pounds, of  which  the  sciences  of  construction  treat,  the 
analogy  is  striking. — Take  some  of  these  real  compounds,  the 
motion  of  a  cannon-ball  impelled  with  a  certain  initial  velocity 
along  a  tangent  to  the  earth,  the  orbit  described  by  Venus  or 
some  other  planet,  a  certain  succession  of  sonorous  or  luminous 
waves.  Each  of  these  compounds  has  its  properties  like  the 
parallelogram  or  the  sphere,  and  the  proposition  connecting 
some  property  to  it,  like  the  theorem  connecting  some  prop- 
erty to  the  parallelogram  or  sphere,  enounces  a  general  law. 
Now,  in  this  compound,  as  in  the  parallelogram  or  sphere,  there 
are  factors  or  more  simple  compounds  which,  introduced  into 
it,  have  brought  with  them  their  characters ;  and  if  the  com- 
pound possesses  the  property  indicated  by  the  law,  it  is  owing, 
as  in  the  parallelogram  or  sphere,  to  the  isolated  or  combined 
characters  of  its  factors.  If  the  cannon-ball  has  a  certain 
range,  describes  a  certain  curve,  and  undergoes  a  certain  dim- 
inution of  velocity,  it  is  owing  to  the  combined  presence  of  a 
particular  initial  impulsion,  of  terrestrial  attraction  and  the 


486  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BooK  IV. 

resistance  of  the  air.  If  two  luminous  rays  are  in  places  ex- 
tinguished by  one  another,  or  if  two  continuous  sounds  are 
at  times  pushed  by  one  another,  it  is  owing  to  the  velocities  of 
the  two  series  of  propagaLed  waves  which,  in  certain  places  and 
at  certain  times,  interfere  with  and  annul  one  another. — Hence 
it  follows  that,  in  the  experimental  as  in  the  geometrical  law, 
the  properties  of  a  more  complex  compound  are  connected 
with  it  through  the  intervention  of  properties  of  its  factors 
or  more  simple  compounds,  that  so  it  is  with  each  of  these 
factors,  and  that  therefore,  if  we  seek  the  ultimate  interme- 
diates, the  ultimate  reasons,  the  ultimate  explanatory  and 
demonstrating  characters  which  establish  the  law,  we  shall 
see  them  recede,  from  the  more  complex  to  the  less  complex 
compounds,  to  permit  themselves  to  be  seized  at  last  in  cer- 
tain very  simple  factors  or  primitive  elements  whose  proper- 
ties they  are. 

In  fact,  in  each  of  the  sciences  we  have  mentioned,  there 
are  some  very  general  laws  corresponding  to  axioms ;  these 
give,  like  axioms,  the  ultimate  reason  of  the  established  law, 
and  they  give  it  because,  like  axioms,  they  enounce  the  prop- 
erties of  the  primitive  factors.  Such,  for  instance,  is  the 
principle  in  applied  mechanics,  that  if  a  body  loses  or  acquires 
a  certain  quantity  of  motion,  the  same  quantity  is  acquired 
or  lost  by  some  other  body.  Such  are  the  two  principles  on 
which  astronomy  is  founded,  the  one  which  attributes  to  the 
planetary  bodies  of  our  system  a  tendency  to  move  in  a 
straight  line  with  a  uniform  velocity  along  the  tangent  to 
their  orbits,  the  other  which  attributes  to  them  a  tendency 
to  fall  towards  each  other  and  towards  the  central  mass,  a 
tendency  in  proportion  to  their  masses  and  inversely  as  the 
squares  of  their  distances.  Such  is,  in  acoustics  and  optics, 
the  assumption  of  elastic  media,  through  which  waves  of  cer- 
tain lengths  are  propagated  with  certain  velocity  in  the  di- 
rection of  their  primitive  impulsions,  or  in  a  direction  per- 
pendicular to  those  impulsions. — From  these  laws  there  flow, 
as  from  so  many  axioms,  a  prodigious  number  of  partial  laws  ; 
and  the  only  difference  separating  sciences  so  constructed  from 
the  mathematical  sciences,  is  that  as,  in  these  last,  the  axioms 
have  been  obtained  by  construction,  we  can  mount  by  analy- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  487 

sis  higher  than  the  axioms,  to  the  principle  of  identity,  which 
is  their  common  scarce,  while  in  the  former,  the  fundamental 
laws  having  been  obtained  by  induction,  to  mount  above 
them  we  must  again  have  recourse  to  induction,  which  to- 
morrow perhaps  we  may  be  able  to  effect,  but  which  to-day 
we  are  unable  to  effect,  and  which  compels  us  provisionally 
to  consider  them  as  primitive,  until  further  discoveries  place 
over  them  more  general  laws,  and  so  depose  them  from  the 
first  to  the  second  rank. 

III.  The  same  arrangement  is  found  in  the  other  less 
advanced  branches  of  experimental  science,  in  the  theory  of 
heat,  of  electricity,  of  chemical,  vital,  and  historical  phenom- 
ena. Here,  too,  the  particular  laws  which  we  first  attain, 
and  which  enounce  the  properties  of  the  more  complex  com- 
pounds, find  their  explanation  and  demonstration  in  the  more 
and  more  general  laws  which  we  subsequently  attain,  and 
which  enounce  the  properties  of  more  and  more  simple  fac- 
tors. Accordingly  as  we  consider  the  different  branches, 
we  find  that  the  operation,  which  is  everywhere  similar,  has 
been  pushed  to  greater  or  less  distances;  experimental 
science,  as  a  whole,  thus  resembles  a  cathedral  commenced  in 
various  points  at  once.  Its  pillars  are  of  unequal  height, 
some  almost  completed,  others  half  built,  others  again 
scarcely  provided  with  their  first  stages.  But  they  all  indi- 
cate by  their  gradual  diminution  and  converging  directions, 
that  a  loftier  arch  must  finally  reunite  them. 

Now  this  constant  convergence  shows  us  in  what  direction 
to  apply  our  efforts,  and  what  subsequent  labor  is  required 
to  continue  the  edifice.  We  have  just  seen  that  the  proper- 
ties of  a  compound  are  connected  with  it  by  intermediates, 
which  are  the  properties  of  its  factors,  components,  or  ele- 
ments ;  Phis  is  the  universal  rule.  These  elements,  then,  are 
what  it  is  principally  necessary  to  discover,  and  it  is  to  their 
properties  that  we  should  direct  our  whole  attention.  The 
more  readily,  therefore,  these  elements  fall  under  our  obser- 
vation, the  more  readily  shall  we  explain  and  demonstrate 
the  properties  of  the  compounds  formed  by  their  assemblage. 
—This  is  precisely  the  case  with  the  most  complex  com- 
pounds of  all,  those  which  are  the  object  of  the  natural  and 


488  TrIE  KNOWLEDGE   OF  GENERAL    THINGS.     [BooK  IV. 

historical  sciences.  And  I  venture  also  to  assert,  that  the 
philosophical  and  higher  portion  of  science  is  nowhere 
more  advanced  than  here.  A  living  body,  plant  or  animal, 
is  a  society,  of  organs  ;  now,  each  of  these  organs  is  suffi- 
ciently large  to  be  grasped  by  our  senses,  measured  by  our 
instruments,  detailed  by  our  descriptions,  pictured  by  our 
drawings.  It  lends  itself  directly  to  study,  and  compared 
with  those  analogous  to  it,  manifests  properties  which,  joined 
with  those  of  its  associates,  explain  the  character  of  the  body 
whose  elements  they  are. — There  are  two  properties  common 
to  all  the  organs  of  a  living  body.  One  of  them,  mentioned 
above,*  and  explained  at  length  by  Cuvier,  is  the  property  of 
being  useful,  which  imposes  on  the  organ  the  obligation  of  its 
characters  harmonizing  with  those  of  all  the  other  associated 
organs,  in  such  a  way  as  to  bring  about  some  total  and  final 
effect,  that  is  to  say  to  render  possible  a  certain  kind  of  life, 
carnivorous,  frugivorous,  insectivorous,  in  the  water,  in  the 
air,  or  on  land,  in  presence  of  certain  prey  and  certain  ene- 
mies, in  short,  in  a  certain  medium ;  we  have  indicated  the 
infinite  consequences  of  this  property  of  every  organ  ;  they 
are  so  numerous  and  so  certain  that  anatomists  have  re- 
constructed fossil  animals  from  some  of  their  fragments. 
There  is  a  second  property,  discovered  by  Geoffroy  Saint- 
Hilaire,  and  still  more  fruitful  in  consequences,  that  of  holding 
a  place  in  a  plan.  By  the  first,  the  organ  is  an  instrument 
which  fulfils  an  office  ;  by  the  second,  it  is  a  part  appertain- 
ing to  a  type.  In  this  respect,  whatever  be  the  secondary 
modifications  imposed  on  it  by  its  passage  from  one  animal 
to  a  different  one,  and  its  consequent  adaptation  to  a  new 
usage,  it  remains  fundamentally  the  same ;  it  is  never  trans- 
posed ;  we  find  it  always  in  the  same  place,  and  it  shows  itself 
through  all  the  elongations,  consolidations,  impoverishments, 
changes  of  part,  and  even  losses  of  employment,  which  it  has 
undergone  in  its  deformed,  transformed,  and  atrophied  state. 
The  same  group  of  anatomical  articulations  supplies  the  arm 
and  hand  in  man,  the  wing  in  the  bat,  the  paw  in  the  cat, 
the  leg  in  the  horse,  the  fin  in  the  seal ;  the  natatory  bladder 
of  the  fish  is  the  respiring  lung  of  the  mammal.  We  often 

*  Part  ii,  book  iv.   ch.  iii.  p.  495. 


CHAP.  III.]  THE  EXPLANATORY  REASON.  489 

find  in  birds  a  little  useless  bone  on  the  border  of  the  wing, 
furnished,  when  they  are  young,  with  a  nail,  without  use,  ex- 
cept as  representing  a  degraded  finger  ;  the  crawling  boa  has 
vestiges  of  limbs,  and  we  find  in  the  slow-worm  a  rudimen- 
tary shoulder,  sternum,  and  pelvis  ;  the  same  slow-worm  has, 
in  its  youth,  two  small  projecting  tubercles,  the  surviving  and 
temporary  remnants  of  stunted  hinder  limbs.  A  part,  then, 
has  the  property  of  exciting  by  its  presence  the  presence  of 
a  whole  system  of  parts,  arranged  according  to  a  fixed  pat- 
tern, which  gives  us  the  rough  framework  of  the  whole  ani- 
mal, and  has,  besides,  the  property  of  determining  by  its 
structure  and  function,  the  structure  and  function  of  the  other 
parts  which  gives  us  the  whole  structure  and  group  of  the 
functions  of  the  complete  animal.  In  this  way,  two  proper- 
ties common  to  the  elements  of  the  group  explain  nearly  all 
the  characters  of  the  group,  and  philosophical  anatomy  fur- 
nishes the  reason  of  the  laws  which  descriptive  anatomy  had 
ascertained. 

And  so,  in  those  human  societies  whose  fixed  or  changing 
characters  are  the  subject-matter  of  history,  the  elements, 
which  are  readily  seized,  enable  us  to  comprehend  the  whole. 
For  these  elements  are  the  human  individuals  of  whom  a 
society  at  any  given  epoch  is  the  collection  only,  and  we 
have  no  difficulty  in  detecting  their  common  characteristics. 
By  means  of  existing  records,  and  by  the  exact  processes  of 
methodical  reconstruction,  we  are  at  present  able  to  suppress 
the  distance  of  time  so  as  to  represent  to  ourselves  by  more 
or  less  numerous  specimens,  the  Frenchman  or  Englishman 
of  the  seventeenth  century  or  of  the  Middle  Ages,  the 
ancient  Roman  and  even  the  Hindoo  of  the  Buddhist  epoch, 
to  picture  to  ourselves  his  life,  private,  public,  industrial,  ag- 
ricultural, political,  religious,  philosophical,  literary,  in  short, 
to  construct  the  descriptive  psychology  of  his  moral  and 
mental  state  and  the  circumstantial  analysis  of  his  physical 
and  social  medium,  then,  to  pass  from  these  elements  to  still 
simpler  elements,  to  discern  the  aptitudes  and  tendencies 
which  were  found  effective  and  preponderant  in  all  the  pro- 
cesses of  his  mind  and  heart,  to  note  the  general  conceptions 
which  determined  every  detail  of  his  ideas,  to  mark  the  gen- 


490  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BooK  IV 

eral  inclinations  which  determined  the  directions  of  all  his 
actions  ;  in  short,  to  distinguish  the  primordial  forces  which, 
present  and  in  action  at  each  moment  of  the  life  of  each  in- 
dividual, impress  on  the  total  group,  that  is  to  say  on  the 
society  and  the  age,  the  characters  which  observation  has  rec- 
ognized there.*  Wherever  we  are  able  thus  to  isolate  and 
observe  the  elements  of  a  compound,  we  can,  from  the  prop- 
erties of  the  elements,  explain  the  properties  of  the  com- 
pound, and,  from  a  few  general  laws,  can  deduce  a  host  of 
particular  laws.  This  is  what  we  have  done  here ;  we  have 
first  descended  by  degrees  to  the  ultimate  elements  of  cog- 
nition, to  ascend  thence  stage  by  stage  up  to  our  simplest 
cognitions,  and  thence,  still  by  degrees,  up  to  more  complex 
ones  ;  in  this  scale,  each  step  possesses  its  characters  by  the 
intervention  of  characters  which  were  manifested  in  the  lower 
steps. 

This  is  why,  when,  in  this  progressive  decomposition,  we 
arrive  at  compounds  in  which  our  consciousness,  senses,  and 
instruments  are  unable  to  discover  simpler  elements,  expla- 
nation is  at  a  standstill  and  is  reduced  to  conjectures.  On 
our  road  we  have  met  with  sensations,  those  of  touch,  smell, 
and  taste,  in  which  we  have  been  unable  to  distinguish  ele- 
mentary sensations,  and  all  that  analogy  permits  us  is  to  con- 
ceive that  there  are  such.  A  similar  limit  is  created  by  a 
similar  difficulty  in  the  other  experimental  sciences. — By 
means  of  the  microscope,  physiologists  and  embryogenists 
have  resolved  living  tissues  into  anatomical  elements,  little 
bodies  which  are  most  frequently  cells  of  various  forms  and 
variously  grouped  ;  but  they  have  not  grasped  the  elements 
of  the  cell,  they  are  ignorant  of  their  properties,  at  least, 
they  are  not  at  present  ignorant  of  them;  in  the  liquid  form- 
less pulp  which  becomes  organized  into  a  little  cell  furnished 
with  a  nucleus,  they  are  unable  to  distinguish  the  particles  and 
d  fortiori  to  distinguish  their  properties.  At  the  most,  they 
conjecture  that  these  elements  are  chemical  molecules  of  ex- 


*  I  have  attempted  to  apply  this  method  in  many  historical  essays,  and  have 
explained  it  in  the  preface  to  "  Essais  de  Critique  et  d'Histoire,"  and  in  that  to 
"  Historic  de  la  Litteraturc  Anglaise." 


CHAP.  III.]  THE  EXPLANATORY  REASON,  49! 

treme  complexity,  and  that  their  mutual  reactions  group 
them  in  a  certain  visible  form.— So  again,  chemists  and  phys- 
icists establish  by  their  experiments  that  the  ultimate  par- 
ticles of  a  homogeneous  body  are  molecules  or  little  masses 
exactly  alike,  that,  if  the  body  is  simple  like  oxygen,  each 
molecule  is  simple  and  consists  entirely  of  oxygen ;  that,  if 
the  body  is  compound  like  water,  each  molecule  is  composed 
of  two  or  more  little  elementary  masses,  one  of  which  is 
oxygen  and  the  other  hydrogen.  But  as  to  these  molecules, 
no  one  has  seen  or  can  see  them  ;  we  are  ignorant  of  their 
form,  their  weight,  their  distance,  their  mutual  situation,  the 
magnitude  of  the  attracting  and  repelling  forces  which  main- 
tain them  in  equilibrium,  the  amplitude  and  velocity  of  the 
vibrations  which  we  suppose  they  have  about  a  supposed 
centre  of  oscillation.  At  the  most,  following  these  indica- 
tions, we  conclude  that,  from  these  unknown  properties,  are 
derived  the  known  properties  of  the  whole  body,  the  greater 
or  less  affinity  it  has  for  some  other  body,  the  reaction  it  ex- 
cites or  undergoes,  the  property  it  has  of  combining  with 
some  other  body  in  definite  and  invariable  proportions,  the 
equivalence  of  a  certain  weight  of  the  first  and  a  certain 
other  weight  of  the  second  to  combine  with  the  same  weight 
of  a  third,  etc. 

In  face  of  elementary  sensations,  living  cells,  chemical 
molecules,  ethereal  atoms,  the  scientific  man  is  in  the  posi- 
tion of  a  short-sighted  person  before  ant-hills  of  various  kinds  ; 
his  dull  sight  can  only  attain  effects  of  the  mass,  changes  of 
the  whole,  the  entire  form  of  the  edifice ;  the  little  workmen 
escape  him  ;  he  does  not  see  them  labor.  He  can  take  a 
quarter  or  half  of  one  of  their  constructions,  can  upset  it 
with  its  inhabitants  on  another,  can  observe,  first,  an  agita- 
tion, a  confusion,  then  an  abatement,  an  arrangement,  and  a 
new  development ;  nothing  more.  As  he  is  a  skilful  handler 
of  experience  and  induction,  he  has  finally  recognized  that 
there  are  in  each  heap  invisible  inhabitants,  and  in  each  dif- 
ferent heap  different  inhabitants,  that  certain  mixtures  suc- 
ceed better  than  others,  that  it  is  always  necessary  to  pre- 
serve certain  proportions,  that  after  the  mixture  the  new 
edifice  presents  characters  which  are  not  manifested  in  either 


492  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV 

of  the  two  unmixed  heaps.  But  he  would  require  far  "more 
piercing  eyes  to  discover  the  economy  of  the  two  primitive 
constructions,  the  instinct  of  their  ants,  the  dealings  set  up 
between  the  two  associated  populations,  and  the  final  econ- 
omy of  the  subsequent  edifice  which  they  together  construct. 
Assume  that,  in  these  societies  of  molecules  we  term  bodies, 
the  inhabitants  and  materials  are  one  and  the  same  thing ; 
the  comparison  will  be  exactly  applicable. 

Thus,  at  a  certain  limit,  our  explanation  is  at  a  standstill, 
and  though,  from  age  to  age,  we  push  it  further  on,  it  is 
possible  that  it  may  always  stop  before  a  certain  limit.  If 
ever  we  know  exactly  the  form,  distance,  magnitude,  and 
weight  of  molecules  of  oxygen  or  sodium,  as  well  as  the  am- 
plitude and  velocity  of  their  oscillations,  we  shall  perhaps  be 
in  face  of  a  system  analogous  to  our  solar  system,  a  kind  of 
vortex  whose  roughly  similar  elements  require  a  further  de- 
composition, and  whose  properties  only  admit  of  explanation 
by  the  wholly  different  properties  of  their  elements — so  again, 
with  the  elements  of  their  elements,  and  so  on,  up  to  infinity. 
For  magnitude  is  always  relative  ;  there  is  nothing  to  prevent 
our  molecules  from  having  as  elements  different  molecules  as 
small  with  relation  to  them  as  they  themselves  are  with  rela- 
tion to  a  planet,  and  so  on,  without  truce  or  termination.  In 
this  case,  the  successive  layers  of  more  and  more  simple 
factors  would  differ  as  the  successive  digits  of  a  non-recurring 
decimal. — Perhaps,  on  the  other  hand,  at  a  certain  point  of 
decomposition,  all  difference  between  the  compound  and  the 
factors  is  at  an  end,  and  the  properties  of  the  compound  are 
nothing  more  than  the  sum  of  those  of  its  factors,  just  as  the 
whole  weight  of  a  body  is  nothing  more  than  the  sum  of  the 
weights  of  its  molecules;  in  which  case  the  limit  would  be 
attained,  since,  knowing  the  properties  of  the  compound,  we 
should  thereby  know  the  properties  of  its  final  elements.  In 
this  case,  the  successive  layers  of  more  and  more  simple 
factors  v/ould  be  similar,  after  a  certain  limit,  as  are,  after  a 
certain  limit,  the  successive  digits  of  a  recurring  mixed  frac- 
tion.— But  whether  the  properties  of  the  compound  arid  its 
factors  are  similar  or  different  is  of  no  importance ;  and  we 
invariably  direct  our  observations  or  conjectures  to  the  proper- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  493 

ties  of  the  factors.  The  structure  of  things,  then,  is  the  same 
in  the  sciences  of  experience  as  in  those  of  construction,  and, 
in  both,  the  explanatory  and  demonstrative  intermediate 
which  serves  as  a  link  between  any  property  and  any  com- 
pound is  a  character,  or  a  sum  of  characters,  different  or 
similar,  included  in  the  elements  of  the  compound. 

IV.  There  remains  a  surplus  of  requirement  special  to 
the  experimental  sciences.  When  we  construct  by  thought 
some  number,  some  polygon,  or  some  cylinder,  we  have  not 
to  explain  its  origin ;  it  does  not  in  fact  exist  in  nature  ;  it 
is  possible  only,  and  not  real.  Perhaps  indeed,  with  a  na- 
ture constituted  like  that  which  we  observe,  it  is  not  possi- 
ble;  but  this  is  unimportant.  We  suppose  its  elements 
combined  in  the  required  manner,  and  explain  by  their  prop- 
erties the  properties  of  the  construction  thus  effected,  with- 
out encumbering  ourselves  with  the  inquiry  as  to  the  forces 
by  which  they  were  themselves  assembled.  It  is  enough  for 
us  that  the  compound  is  given ;  we  do  not  inquire  why  it  is 
given. — Things  do  not  happen  thus  when  real  compounds 
are  in  question.  We  are  bound  to  explain  their  properties 
by  the  properties  of  their  elements,  and  further,  to  explain 
the  concurrence  of  their  elements.  Then  come  in  questions 
of  origin,  the  most  curious,  but  most  difficult,  of  all.  For,  as 
this  concurrence  is  in  most  cases  of  very  great  antiquity,  and 
can  have  had  no  witnesses,  we  can  neither  observe  it  directly 
nor  know  it  by  tradition,  and  are  reduced  to  conjecture  it  from 
present  concurrences,  which  are  but  approximately  similar, 
and  are  sometimes  entirely  wanting.  All  the  experimental 
sciences  have  thus  their  historical  chapter,  more  or  less  con- 
jectural, according  as  more  or  less  precise  indications,  more 
or  less  correct  analogies,  more  or  less  complete  records,  per- 
mit our  mental  reconstruction  more  or  less  exactly  to  replace 
the  missing  evidence  of  our  consciousness  or  our  senses. 

For  instance,  there  is  a  question  for  the  astronomer,  as 
to  the  formation  of  the  various  planets,  for  the  geologist,  as 
to  the  formation  of  the  successive  strata  of  the  outer  crust  of 
the  globe,  for  the  mineralogist,  to  discover  how  the  different 
rocks  were  formed,  for  the  naturalist,  to  know  how  our  species 
of  plants  and  animals  were  formed,  for  the  historian,  to  de- 


494  TIIE  KNO  WLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

tect  the  formation  of  the  successive  epochs  of  one  and  the 
same  human  society-,  and  the  different  traits  of  a  national 
character.  They  all  start  from  an  anterior  state  denoted  by 
converging  indications,  or  attested  by  transmitted  records, 
and  from  this  probable  or  certain  state  they  deduce,  accord- 
ing to  existing  laws,  the  following  state,  then  the  next  follow- 
ing state,  and  so  on,  up  to  the  existing  state. 

Thus  Laplace  assumes  that  our  system  was  at  first  an  im- 
mense nebula  extending  round  a  central  nucleus  ;*  that  this 
vast  atmosphere,  becoming  condensed  as  it  cooled,  was  divi- 
ded into  concentric  zones  of  vapor  similar  to  the  rings  of  Sat- 
urn ;  that,  by  a  subsequent  condensation  and  cooling,  these 
zones  became  collected  into  planets,  which  were  first  gaseous, 
then  liquid,  then  solid  ;  and,  from  this  gradual  condensation, 
combined  with  the  law  of  gravitation,  he  deduces,  by  a  mar- 
vellous adjustment,  the  principal  characters  and  even  the 
singular  peculiarities  which  our  system  nowadays  presents. 
— Taking  up  this  supposition  at  the  point  where  Laplace  left 
it,  geologists  trace  with  probability  the  thickening  of  the  ter- 
restrial crust,  and  explain,  from  epoch  to  epoch,  with  gaps  be- 
coming gradually  fewer,  the  deposition  and  superposition  of 
the  strata,  their  partial  upheavals,  their  erosions,  their  rup- 
tures, the  present  disposition  of  our  continents  and  seas,  by  the 
prolonged  play  of  the  mineral  or  organic  forces  in  the  midst 
of  which  we  are  now  still  living.f — At  their  side,  their  allies, 
mineralogists  and  chemists,  see  that  rocks  and  amalgams  sim- 
ilar to  those  which  the  earth  presents  are  formed  under  their 
hands  and  eyes,  by  slow  actions,  by  prolonged  heat,  by  con- 
tinued compression,  by  molecular  additions,:}:  and  from  the 
processes  they  now  observe  in  their  little  artificial  laborator- 
ies, they  draw  conclusions,  with  fitting  precautions,  as  to  the 
analogous  processes  by  which  the  amalgam  and  the  rock  were 
formed  of  old  in  the  great  laboratory  of  nature. 


*  "  Exposition  du  Systeme  du  Monde,"  ii.  425. 

\  See,  as  to  this,  Lyell's  "  Principles  of  Geology." 

\  Crystals  of  granite  have  been  found  at  Plombieres,  in  the  concrete  on  which 
the  Romans  built.  They  have  been  formed  there  by  the  infiltration  of  water  for 
eighteen  hundred  years. — M.  Daubree  and  M.  de  Senarmont  have  produced  in 
their  laboratories  a  great  number  of  natural  compounds. 


CHAP.  III.]  THE  EXPLANATORY  REASON. 

Here  come  in  the  naturalists.     Darwin  starts  with  a  fun- 
damental character  common  to  all  the  species  of  animals  and 
vegetables,  the  struggle  for  life,  from  which  there  follows  the 
destruction  of  all  individuals  less  properly  adapted  to  their 
medium,  the  exclusive  survival  of  the  individuals  best  adapt- 
ed to  their  medium,  the  privilege  these  have  of  propagating 
the  race,  the  successive  acquisition  of  useful  characters,  the 
transmission  to  descendants  of  all  the  accumulated  treasure 
of  useful  characters,  and  finally,  through  this,  the  progressive 
modification  of  the  species,  the  gradual  perfectionment  of  the 
organs,  and  the  slow  adaptation  of  the  individual  to  its  defin- 
itive medium. — Provided  with  this  existing  law,  he  explains, 
by  its  former  presence,  the  assemblage  of  the  organs  of  which 
Geoffrey  Saint-Hilaire  and  Cuvier  had  ascertained  the  prop- 
erties.— By  one  of  these  properties  the  organ  is  a  part  in  a 
plan  and  in  a  type ;  that  is,  the  legacy  of  a  common  ancestor. 
All  mammals  are  descended  from  a  mammal*  "  which  had  its 
limbs  constructed  on  the  existing  general  pattern  which  we 
now  find  throughout  the  whole  class."     All  insects  are  de- 
scended from  an  insect  "  which  had  an  upper  lip,  mandibles, 
and  two  pair  of  maxillae,  these  parts  being  perhaps  very  simple 
in  form."     If  the  type  is  found  to  be  the  same  throughout  so 
many  different  species,  it  is  because  all  these  species  repeat, 
by  virtue  of  inheritance,  the  characteristics  of  their  common 
progenitor. — By  the  other  of  these  properties,  the  organ  is  a 
useful  instrument  which  brings  its  structure  and  function  into 
harmony  with  those  of  the  others,  in  such  a  way  that  the  dif- 
ferent species  can  subsist  in  their  different  media  ;  this  is  be- 
cause, owing  to  continuous  selection,  the  common  pattern  be- 
queathed by  the  common  progenitor  is  modified,  here  in  one 
direction,  there  in  another,  so  as  to  accommodate  its  details 
to  the  differences  and  changes  of  the  medium.     The  same 
parts  of  the  same  limb  become  thin  and  elongated  in  the  bat- 
shortened  and  soldered  in  the  whale,  so  as  to  be  fitted  for  fly- 
ing in  the  first  case,  and  swimming  in  the  second.     If  the 
type  varies  from  species  to  species,  it  is  because  circumstances 


*  Darwin,  on  "  The  Origin  of  Species,"  p.  435. — See,  as  to  the  theory  of  evo- 
lution as  a  whole,  the  very  bold,  precise,  and  most  suggestive  work  of  Ht_iLcn 
Spencer,  "  Principles  of  P.iology." 


496  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  IV. 

have  varied  from  group  to  group,  and  the  variety  of  circum- 
stances has  produced  the  variety  of  acquisitions. — When  this 
is  settled,  we  are  capable  of  tracing  mentally  through  the  im- 
mense duration  of  geological  periods,  from  the  protococcus  and 
amoeba  up  to  man,  the  formation,  addition,  and  assemblage 
of  the  parts  which  now  constitute  an  organized  body.    It  is  a 
living  edifice  in  which  selection  has  superimposed,  from  spe- 
cies to  species,  and  upon  a  common  type  transmitted  by  in- 
heritance, useful  differences.     Just  as,  in  a  house,  the  carpen- 
ters and  masons  first  construct  the  walls  and  lay  down  the 
floors,  after  which  come  joiners,  painters,  and  upholsterers  to 
arrange  the  apartments.   We  see  that  the  second  set  of  work- 
men has  succeeded  to  the  first,  to  resume  and  complete  the 
commenced  construction.     And  so,  many  generations  of  an- 
cestors have  successively  labored  to  construct  each  of  our  spe- 
cies.    One  of  these  generations,  the  primitive  and  most  an- 
cient of  all.  has  established  the  most  general  type  which  is 
common  to  all  animals  of  every  subkingdom,  articulate  or 
vertebrate.     The  second,  a  later  one,  issuing  from  this  last, 
has  superimposed  differences  which  constitute  the  class — that 
is  to  say  the  bird,  the  fish,  or  the  mammal.     Then  has  come 
the  third,  which  starting  with  the  mammal,  has  elaborated 
the  transmitted  work  and  formed  families — that  is  to  say  the 
cetacea,  the  cheiroptera,  the  ruminantia,  the  carnivora,  the 
primates.      Then,  finally,  have  the  descendants  of  the  pri- 
mates, by  their  distinct  developments  and  increasing  diver- 
gencies, constituted  genera,  the  gorilla,  the  orang-outang,  and 
man,  the  latter  being  distinguished  from  the  rest  by  a  partic- 
ular conformation  of  limbs,  and  a  more  delicate  structure  of 
the  brain. 

Here  comes  in  the  historian  :  he  takes  a  people  at  a  given 
moment.  By  the  combined  influence  of  the  former  state  and 
of  hereditary  aptitudes  and  faculties,  he  explains  the  social, 
intellectual,  and  moral  state  at  the  given  moment  ;  by  the 
combined  influence  of  this  new  state  and  of  the  same  heredi- 
tary aptitudes  and  tendencies,  he  explains  the  social,  intel- 
lectual, and  moral  state  at  the  later  moment,  and  so  on,  either 
by  reascending  the  course  of  time  from  the  contemporary 
epoch  up  to  the  most  ancient  beginnings  of  history,  or  by  de- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  497 

scending  the  course  of  time  from  the  most  ancient  beginnings 
of  history  down  to  the  contemporary  epoch. — We  may  con- 
ceive that  in  this  prodigious  evolution,  which  extends  from 
the  formation  of  the  solar  system  to  that  of  modern  man,  the 
gaps  are  great  and  numerous ;  this  is  in  fact  the  case,  and  our 
materials  for  filling  them  are  often  reduced  to  conjectures.  A 
history  like  this  is  a  torn,  blotted  book,  in  which  some  chap- 
ters, the  last  especially,  are  almost  entire,  in  which,  of  other 
earlier  ones,  there  subsist  but  two  or  three  scattered  pages, 
in  which,  of  the  earliest  chapters,  the  titles  alone  remain. — 
But  every  day  a  new  discovery  restores  a  page,  and  the  sagac- 
ity of  scientific  men  has  detected  some  portion  of  the  general 
thought.  Thus  it  is  that,  within  the  last  fifteen  years,  we 
have  rediscovered  the  traces  and  marked  the  successive  ad- 
vances of  the  human  race  preceding  our  geological  epoch  ; 
and  an  entirely  recent  law,  that  of  the  conservation  of  «force, 
derives  by  transformation  all  existing  forces  from  the  primi- 
tive forces  which  the  nebula  of  Laplace  comprised  in  its  ear- 
liest state.* 

From  all  these  great  fragments  of  rigorous  or  approxima- 
tive explanation,  a  universal  truth  is  manifested :  that  the 
question  of  origins  is  no  more  mysterious  than  that  of  char- 
acters. When  given  a  compound,  its  properties  are  explained 
by  the  properties  of  its  united  elements.  When  given  this 
union,  it  is  explained  by  the  properties  of  these  same  ele- 
ments and  by  the  antecedent  circumstances.  It  is,  like  so 
many  others,  an  effect  only,  and,  like  all  the  others,  it  has  as 
reason  the  combined  presence  of  a  group  of  fixed  with  a 
group  of  changing  conditions. — To  form  the  planet,  there  was 
a  fixed  state,  the  gravitation  of  the  gaseous  molecules  carried 
round  the  central  nucleus,  and  a  changing  condition,  the  pro- 
gressive cooling  and  consequent  gradual  condensation  of  these 
same  molecules. — To  form  the  species,  there  was  a  fixed  con- 
dition, the  transmission  of  an  older  general  type,  and  chang- 
ing conditions,  the  new  circumstances  which,  selecting  the 
subsequent  ancestors,  added  to  the  type  the  characters  of  the 
species. — To  form  a  particular  historical  epoch,  there  was  a 

*  See,  as  to  this,  Helmholtz,  "  Metnoire  sur  la  Conservation  de  la  Force"  (tr. 
Purard),  pp.  31-34  et  seq. 
32 


THE  KNOWLEDGE   OF  GENERAL    THINGS.     [BOOK  IV. 

fixed  condition,  the  maintenance  of  the  national  character, 
and  a  changing  condition,  the  new  state  in  which  the  nation 
happened  to  be  placed  on  emerging  from  the  preceding  epoch. 
— Hence  it  follows  that,  in  questions  of  origin,  as  in  other 
questions,  there  is  an  explanatory  and  demonstrative  interme- 
diate, that  the  re-union  of  the  elements  has  its  reason  of  exis- 
tence, just  as  the  characters  of  the  compound  have  their  rea- 
son of  existence,  that  it  is,  like  them,  a  product,  and  that  all 
the  difference  between  the  two  products  consists  in  this,  that, 
as  the  first  is  historical  and  the  second  not  historical,  the  first 
comprises  a  factor  more  than  the  second,  namely,  the  influ- 
ence of  the  historical  moment,  that  is  to  say  of  the  prelimin- 
ary circumstances  and  the  antecedent  state. 

§  HI- 

I.  Let  the  reader  now  collect  and  glance  over  the  conclu- 
sions to  which  we  have  just  arrived  ;  he  will  find  that  they 
converge,  and  will  be  led  by  their  convergence,  towards  a 
universal  law  of  a  higher  order,  which  governs  every  law. 
Take  any  couple  whatever  of  any  data  whatever ;  as  soon  as 
they  are  actually  connected,  there  is  a  reason,  a  because,  an 
intermediate  which  explains,  demonstrates,  and  necessitates 
their  connection. — This  is  true  for  cases,  or  couples  of  par- 
ticular data,  just  as  for  laws  strictly  so  called,  or  couples  of 
general  data ;  there  is  a  reason  for  the  fall  of  this  leaf  which 
has  just  come  to  the  ground,  and  for  the  gravitation  of  all 
the  planets  towards  the  sun,  for  this  night's  dew,  and  for  the 
liquefaction  of  all  vapor,  for  the  beat  of  the  pulse  I  feel  at 
this  very  moment  in  my  wrist,  and  for  the  presence  of  any 
function  or  apparatus  in  any  living  being. — It  is  true  for  the 
laws  in  which  the  first  datum  is  a  more  complex  compound, 
as  for  the  laws  in  which  the  first  datum  is  a  more  simple 
compound  ;  there  is  a  reason  for  the  total  acts  of  a  human 
society,  and  for  the  individual  acts  of  its  members,  for  the 
properties  of  a  chemical  compound,  and  for  the  properties  of 
its  constituent  substances,  for  the  effects  of  a  machine,  and 
for  the  effects  of  its  wheelwork. — It  is  true  again  for  the  laws 
concerning  mental  compounds  as  for  the  laws  concerning 
real  compounds;  there  is  a  reason  for  the  properties  of 


CHAP.  III.]  THE  EXPLANATORY  REASON. 


499 


the  ellipse  or  cylinder  as  for  the  properties  of  water  or  of 
granite. — It  is  true  again  for  the  laws  governing  the  forma- 
tion of  a  compound  as  for  those  by  which  it  possesses  its  char- 
acters ;  there  is  a  reason  for  the  formation,  as  well  as  for  the 
properties,  of  a  planet  or  of  a  species. — But  the  most  remark- 
able point  is,  that  it  is  true  for  the  laws  whose  explanation  is 
still  wanting  as  for  those  whose  explanation  we  now  possess. 
There  is  a  reason  for  the  attraction  which  all  masses  exercise 
on  one  another,  for  the  properties  of  oxygen,  for  the  forma- 
tion of  a  living  cell,  for  the  origin  of  our  nebula.  At  all 
events,  we  believe  this.  We  cannot  show  this  reason,  but  we 
are  persuaded  that  it  exists ;  we  anticipate  it  by  a  bold  affirm- 
ation as  to  our  future  discoveries,  and  even  as  to  discoveries 
which  perhaps  we  shall  never  make. 

Besides  this,  we  indicate  beforehand  the  position  and 
principal  characteristics  of  the  intermediate  which  still  escapes 
us. — We  assume  that  if  two  masses  attract  one  another,  it  is 
by  virtue  of  a  simpler  and  more  general  character,  included  in 
the  group  of  characters  which  constitute  these  masses,  such 
as  would  be  an  incessantly  repeated  impulsion  superadding 
at  every  moment  an  effect  to  the  preceding  effect,  which  we 
express  by  saying  that  attraction  is  a  force  whose  action  is 
not  momentary  but  continuous,  which  enables  us  to  conceive 
the  velocity  of  the  falling  mass  as  the  sum  of  all  the  velocities 
acquired  since  the  first  moment  of  its  fall,  which  has  led  some 
physicists  to  explain  the  attraction  of  two  masses  by  the 
continuous  impulsion  of  a  surrounding  ether. — We  assume 
that  if  oxygen  presents  such  or  such  characters,  it  is  by 
virtue  of  simpler  and  more  general  characters  appertaining  to 
its  elements,  and  consisting  of  the  masses,  distances,  and 
internal  movements  of  its  component  atoms. — We  assume 
that  if  a  formless  liquid  becomes  organized  into  a  cell,  it  is 
owing  to  the  mutual  reactions  and  previous  state  of  the  very 
complex  particles  of  which  it  is  the  aggregate,  and  that  if 
our  nebula  formerly  sprung  into  being,  it  was  due  to  the  forces 
of  its  molecules,  and  to  the  influence  of  a  previous  state  which 
vre  cannot,  even  by  conjecture,  represent  to  ourselves. — In 
our  view,  not  only  does  the  explanatory  and  demonstrative 
intermediate  exist  in  all  these  couples,  though  it  may  elude 


5QO  THE  KNOWLEDGE  OF  GENERAL    THINGS.       [BOOK  IV. 

our  grasp ;  but  further,  it  is  a  simpler  and  more  general  char- 
acter than  the  first  datum  of  the  couple,  it  is  included  in  that 
datum  and  appertains  to  its  elements,  and  the  properties  of 
that  datum,  as  well  as  its  origin,  have  as  their  ultimate  reason 
of  existence  the  characters  and  previous  state  of  its  ultimate 
elements. 

On  these  indications,  our  thought  flies  off  to  extend  this 
structure  of  things  beyond  our  world  and  history,  throughout 
the  two  gulfs  of  space  and  time,  beyond  all  the  distances  to 
which  imagination  can  attain,  beyond  all  the  confines  which 
numbers  or  quantities,  fruitlessly  swollen  and  heaped  to- 
gether, can  denote  to  the  pure  reason.  Are  we  justified 
in  acting  thus?  And  what  motives  can  we  allege  to  au- 
thorize a  supposition  which  anticipates,  not  only  all  future 
experience,  but  all  possible  experience,  and  involves  in  the 
immensity  of  its  forecast  the  immensity  of  the  universe? 

II.  Two  series  of  cases  confront  us,  a  considerable  one 
made  up  of  all  the  facts  and  laws  whose  reason  we  know, 
another  prodigiously  disproportioned  and  infinitely  greater, 
since  it  is  infinite  and  made  up  of  all  the  facts  and  laws  whose 
reason  we  do  not  know.  Here  are  two  indications,  one 
positive,  the  other  negative,  one  favorable  to  our  supposi- 
tion, the  other  seemingly  unfavorable. — But  this  unfavora- 
bleness  is  apparent  only.  For  if,  when  we  know  the  reason 
of  a  fact  or  law,  we  can  conclude  its  existence,  we  cannot, 
from  our  ignorance  of  it,  conclude  its  absence.  This  reason 
may  exist,  though  unknown,  and,  in  fact,  if  we  look  back  on 
the  past  states  of  our  knowledge,  we  find  that  on  many  oc- 
casions it  existed,  though  unknown.  We  see  daily,  in  pro- 
portion as  science  becomes  extended  and  precise,  the  first 
series  increasing  at  the  expense  of  the  second,  and  analogy 
leads  us  to  believe  that  cases  still  comprised  in  the  second  are 
similar  to  those  which  have  ceased  to  be  comprised  in  it. 
The  further  our  extended  experience  drives  back  our  horizon 
in  time  and  space,  the  more  explanatory  reasons  do  we  add  to 
our  store.  It  is  sufficient  to  examine  the  history  and  nature 
of  experimental  science  to  recognize  that,  if  there  were  or 
still  are  voids  in  this  store,  it  never  arises  from  the  explana- 
tory reason  failing  or  having  failed  in  things,  but  always  from 


CHAP.  III.]  .THE  EXPLANATORY  REASON.  501 

its  failing  or  having  failed  in  our  minds.  It  was  existing  in 
nature ;  but  scientific  men  were  imperfectly  instructed,  and 
had  not  yet  discovered  it.  It  now  exists  in  nature ;  but  we 
are  unable,  and  perhaps  shall  never  be  able,  to  detect  it  there. 
The  gap  arises  not  through  its  absence,  but  through  our  ig- 
norance or  impotence,  and  the  fault  is  not  in  things,  but  in 
ourselves. — If  in  Kepler's  days  the  motion  of  the  planets 
could  not  be  explained,  it  was  because  gravitation  was  then 
unknown.  If,  at  present,  we  are  unable  to  explain  why  pure 
carbon,  according  to  its  different  states,  furnishes,  with  the 
same  molecules,  compounds  as  different  as  the  diamond  and 
graphite,  it  is  because  we  do  not  know  the  velocities  and 
masses  of  its  molecules,  and  so  cannot  define  their  various 
states  of  equilibrium.  To  detect  the  explanatory  reason, 
as  we  have  defined  it,  certain  conditions  are  required,  and 
if  these  conditions  are  not  fulfilled,  the  reason  may  indeed  be 
present,  we  shall  not  be  able  to  distinguish  it.  To  detect  the 
reason  explaining  the  characters  of  a  compound  like  graphite, 
it  is  necessary  that  we  should  know  the  properties  of  its  ele- 
ments, the  molecules  of  carbon.  To  detect  the  reason  which 
explains  the  origin  of  the  first  organic  compound,  it  is  neces- 
sary that  we  should  know,  besides  the  properties  of  its  ele- 
ments, the  primordial  circumstances  in  which  they  were 
assembled.  This  is  why  we  shall  be  unable,  while  these 
preliminaries  fail  us,  to  know  the  explanatory  reason.  So 
long  as  they  are  attained  by  simple  conjecture,  it  will  be  at- 
tained by  simple  conjecture,  and  we  shall  be  at  a  greater  or 
less  distance  from  it,  according  as  we  are  a  greater  or  less 
distance  from  them. — Hence  it  follows  that  our  ignorance  of 
it  is  never  an  indication  of  its  absence,  from  which  it  follows 
that  we  have  no  ground  to  suppose  its  absence,  at  any  period 
even  for  events  which  preceded  the  origin  of  our  nebula,  or 
at  any  place  even  beyond  the  furthest  points  of  the  visible 
firmament.  That  our  experimental  science  has  gaps  is  incon- 
testable :  but  its  structure  is  sufficient  to  account  for  them, 
and  it  is  against  all  the  rules  of  hypothesis  to  account  for 
them  by  the  arbitrary  and  useless  addition  of  an  unascer- 
tained cause  to  the  ascertained  cause  which  is  sufficient. 

Excluded  on  one  side,  presumptions  are  compelled  to  turn 


5O2  THE  KNOWLEDGE  OF  GENERAL  THINGS.      [BOOK  IV. 

to  the  other.  As  there  is  no  choice  except  between  the  pres- 
ence and  absence  of  the  explanatory  reason,  the  chances, 
when  no  longer  in  favor  of  its  absence,  become  in  favor  of 
its  presence,  and  the  balance  inclines  towards  the  other  scale. 
—It  would  incline  further  still  in  this  direction  if  we  could 
point  out  sciences  free  from  the  conditions  imposed  on  ex- 
perimental science,  and  thereby  finding  an  explanatory  reason 
for  all  their  laws.  For  such  a  contrast  would  afford  room 
for  the  belief  that  the  gaps  of  experimental  science  have 
the  conditions  to  which  it  is  subject,  not  only  as  their 
sufficient,  but  also  as  their  single  cause  ;  from  which  it  would 
follow  that  experimental  science,  when  freed  from  thes*e  con- 
ditions, would  thereby  fill  up  these  gaps,  and  that  the  explan- 
atory reason,  being  everywhere  discovered,  would  exist  every- 
where.— Now  this  is  precisely  the  contrast  presented  by  the 
sciences  of  construction  when  compared  with  the  sciences  of 
experience.  In  the  first,  all  the  explanatory  and  demonstra- 
tive intermediates  which  connect  any  property  to  any  com- 
pound, from  the  first  to  the  last,  are  known  and  therefore 
exist ;  there  is  not  one  of  their  laws  which  does  not  manifest, 
and  which  therefore  does  not  possess,  its  because  and  its  rea- 
son.— It  is  to  be  presumed,  then,  that  if  we  could  employ  in 
our  experimental  sciences  the  processes  we  employ  in  our 
sciences  of  construction,  we  should  arrive  at  the  same  dis- 
coveries, and  that  just  as  every  law  in  the  last  has  its  reason 
of  existence,  so  has  every  law  in  the  first. 

This  probability  becomes  stronger  still,  when  we  observe 
that  the  laws  of  the  second  may  be  discovered,  like  the 
laws  of  the  first,  by  the  inductive  method,  and  that  if  we 
follow  this  method  in  the  second  as  in  the  first,  the  reason  of 
the  law  then  remains  unknown  though  present.  Conse- 
quently, the  inductive  process  is  the  sole  cause  of  our  ignor- 
ance in  this  case :  hence  it  follows  with  all  probability  that 
in  other  cases,  that  is  to  say  in  the  experimental  sciences,  it 
is  still  the  sole  cause  of  our  ignorance,  and  that,  in  other 
cases  as  in  this,  the  explanatory  reason  is  always  present, 
though  it  may  always  elude  us. — In  fact,  suppose,  as  we  did 
before,*  the  case  of  a  man  of  very  exact  and  very  patient  mind, 

*  Part  ii,  book  iv.,  chap,  ii,  p.  451. 


CHAP.  III.]  THE  EXPLANATORY  REASON,  503 

very  skillful  at  induction,  but  capable  of  induction  only  ;  we 
request  him  to  ascertain  the  number  of  right  angles  to  which 
the  angles  of  any  quadrilateral  are  together  equal.  Let  us 
assume  this  time  that  he  has  at  hand  a  number  of  perfect 
quadrilaterals,  that  his  instruments  of  measurement  are  per- 
fect, and  that  he  applies  them  with  perfect  exactness.  By  a 
series  of  inductions  similar  to  those  we  have  described,  he 
will  finally  discover  that  the  angles  of  every  quadrilateral  of 
whatever  kind,  trapezium,  parallelogram,  rhombus,  rectangle, 
or  square,  are  together  equal  to  four  right  angles ;  but 
his  knowledge  of  quadrilaterals  will  stop  here,  that  is  to  say 
at  the  point  attained  by  the  most  advanced  branches  of  our 
experimental  science.  He  will  ascertain  a  law  which  will  be 
inexplicable  to  him,  just  as  some  chemical  or  physical  law  is 
inexplicable  to  us.  He  will  have  connected  to  every  quadri- 
lateral a  constant  property,  the  equality  of  its  angles  to  four 
right  angles,  as  we  connect  to  every  white  crystal  of  carbon 
a  constant  property,  octohedric  structure.  But  he  will  not 
have  discovered,  any  more  than  ourselves,  the  intermediate 
which  necessitates  the  connection.  In  his  case,  this  interme- 
mediate  is  a  property  of  the  two  elementary  triangles  of  which 
the  quadrilateral  is  the  possible  sum.  In  our  case,  this  inter- 
mediate is  a  property  of  the  elementary  molecules  of  which 
the  white  crystal  of  carbon  is  the  real  sum.  He  will  miss  his 
intermediate,  then,  as  as  we  miss  ours,  by  a  defect  of  method, 
which  can  be  remedied  in  his  case,  but  which  cannot  be  reme- 
died in  ours.  We  have,  then,  every  ground  for  belief  that  if, 
like  him,  we  could  apply  a  remedy,  and  if  to  inductive  ex- 
perience we  could  add,  in  our  case,  as  in  his,  deductive  analy- 
sis by  way  of  supplement,  the  attained  intermediate  would 
manifest  its  presence  in  our  case  as  it  does  in  his. 

We  thus  arrive  at  considering  the  sciences  of  construction 
as  a  preliminary  copy,  a  reduced  model,  an  indication  reveal- 
ing to  us  what  the  sciences  of  experience  might  be,  an  indi- 
cation similar  to  the  little  waxen  edifice  which  architects 
construct  beforehand  with  a  more  manageable  substance,  to 
represent  on  a  small  scale  the  proportions  and  total  aspect  of 
the  great  monument  they  are  in  process  of  erecting,  and 
which  perhaps  they  will  never  complete. — In  fact,  if  we  look 


504  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

at  the  ideal  and  the  real  world,  we  perceive  that  their  struc- 
ture is  similar.  In  the  first,  as  in  the  second,  there  are  ele- 
ments and  compounds,  elements  of  elements  and  compounds 
of  compounds,  objects  capable  of  being  classified,  species, 
genera,  and  families,  families  of  lines  and  surfaces  ranged  be- 
neath one  another  according  to  the  degree  of  their  equations, 
less  general  laws  explained  by  more  general  laws,  and  a  num- 
ber of  other  characteristics  no  less  essential,  and  common  to 
both.  Therefore,  the  two  orders  are  analogous. — But,  be- 
sides, all  the  materials  of  the  first  are  found  in  the  second. 
For  we  have  seen  that  numbers,  lines,  surfaces,  solids,  mo- 
tions, velocities,  forces,  exist,  not  only  in  the  mind,  but  also 
in  nature;  it  is  in  nature  that  the  mind  discovers  them,  and 
from  nature  that  it  extracts  them.  All  its  special  work  con- 
sists in  combining  them  in  its  own  way,  without  troubling  it- 
self to  inquire  whether  there  are  in  nature  real  outlines  which 
adapt  themselves  to  the  mental  outlines,  whether  there  is  any 
actual  sphere  or  ellipse  corresponding  to  the  ideal  sphere  or 
ellipse. — There  remains,  then,  a  single  difference  which  separ- 
ates our  artificial  compounds  from  natural  compounds ;  the 
first  are  more  simple,  and  the  second  more  complex ;  Euclid's 
straight  line  is  simpler  than  the  imperceptibly  bent  line 
which  a  ball  describes  in  the  first  metre  after  it  leaves  the 
cannon ;  the  slightly  indented  ellipse  described  by  a  planet 
is  more  complex  than  the  geometrical  ellipse.  For  this  rea- 
son we  study  the  mental  compound  before  the  real  com- 
pound, and  the  knowledge  of  the  first  leads  us  to  the  know- 
ledge of  the  second.  Herein  lies  the  whole  secret  of  the  ser- 
vices which  the  sciences  of  construction  render  to  the  sciences 
of  experience  ;  thus  it  is  that  the  first  have  their  application 
in  the  second.  Given  two  compounds,  one  mental,  the  other 
real,  they  become  adapted  to  one  another  with  this  differ 
ence,  that  the  second  comprises  supplementary  and  perturb 
ing  elements  in  addition  to  the  elements  which  constitute 
the  first,  and  this  renders  the  first  simpler,  and  the  second 
more  complex.  We  take  account,  by  turns,  of  this  general 
adaptation  and  this  subsidiary  difference.  We  discover  by 
the  sciences  of  construction,  the  properties  of  the  first  com- 
pound, the  geometrical  straight  line  or  ellipse ;  then,  on  ac- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  505 

count  of  this  general  adaptation,  we  attribute  them  provi- 
sionally to  the  path  of  the  bullet  or  the  planet's  ellipse ;  and 
thus  obtain  ideas  which  are  almost,  but  not  wholly,  exact 
Having  done  this,  on  account  of  this  subsidiary  difference, 
we  gladly  introduce  into  our  ideas  the  supplementary  and 
perturbing  elements  in  nature  which  bend  the  path  of  the 
ball  or  indent  the  planet's  ellipse.  Thus,  from  the  provisional 
path  and  ellipse,  which  were  too  simple,  and  therefore  ap- 
proximate only,  the  mind  passes  gradually  to  the  definitive 
path  and  ellipse  which,  while  growing  complicated,  become 
exact.  By  this  progressive  rectification,  our  idea,  which  was 
at  first  rigorously  adjusted  to  the  ideal  compound  only,  finally 
becomes  rigorously  adjusted  to  the  real  compound.  It  was 
in  a  science  of  construction  that  it  took  its  origin,  and  it  is 
in  a  science  of  experience  that  it  finds  its  use. 

Hence  follows  a  consequence  of  capital  importance,  that 
at  every  place  and  time,  outside  our  history  and  world,  as 
well  as  in  our  history  and  world,  the  theorems  are  capable  of 
being  applied.  In  fact,  it  is  sufficient  for  this  that  the  real 
compounds,  whether  near  or  distant,  should  enter  into  our 
mathematical  outlines,  and  they  necessarily  enter  them,  when 
they  have  number,  situation,  or  form,  when  they  possess  mo- 
tion, velocity,  or  mass,  when  they  are  subject  to  forces,  that 
is  to  say  to  any  conditions  of  motion.  Stuart  Mill,  then,  is 
wrong  to  say  that  "  in  distant  parts  of  the  stellar  regions, 
where  the  phenomena  may  be  entirely  unlike  those  with  which 
we  are  acquainted,  it  would  be  folly  to  affirm  confidently  the 
prevalence  of  any  law,  general  or  special,"  and  that,  "  any  one 
accustomed  to  abstraction  and  analysis,  who  will  fairly  exer- 
cise his  faculties  for  the  purpose,  will,  when  his  imagination 
has  once  learnt  to  entertain  the  notion,  find  no  difficulty  in 
conceiving  that  in  some  one,  for  instance,  of  the  many  firma- 
ments into  which  sidereal  astronomy  now  divides  the  uni- 
verse, events  may  succeed  one  another  at  random,  without 
any  fixed  law  ;  nor  can  anything  in  our  experience,  or  in  our 
mental  nature,  constitute  a  sufficient,  or  indeed  any,  reason 
for  believing  that  this  is  nowhere  the  case." — No  doubt  it  is 
possible  that  bodies  do  not  there  attract  one  another.  But 
there,  as  with  us,  if,  through  the  application  of  any  force,  a 


506  THE   KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

body  takes,  for  a  time  as  short  as  we  please,  a  uniform  recti- 
linear motion,  it  will  tend  to  continue  it  indefinitely  ;  for,  the 
axiom  being  necessary,  as  soon  as  the  first  of  its  two  data  ex- 
ists in  fact,  the  second  cannot  fail  to  exist  in  fact. — And 
moreover,  whatever  be  the  body  and  whatever  be  its  motion, 
if  this  motion  be  regarded  in  a  purely  mechanical  aspect,  it 
will,  there  as  with  us,  be  necessarily  wholly  determined  by 
the  magnitudes  and  directions  of  the  forces  whose  effect  it  is ; 
so  that,  there  as  with  us,  it  will  be  found  by  the  solution  of  a 
mechanical  problem,  and  will  only  resist  solution,  if  the  com- 
plication of  its  elements  be  so  great  that  our  formulae  are  not 
yet  sufficiently  advanced  to  comprehend  them ;  for,  not  only, 
as  we  have  seen,  are  the  sciences  of  construction,  being  nec- 
essary, universal,  but  again,  their  application  is  thereby  uni- 
versal. Indeed  real  compounds,  so  far  as  they  are  formed  of 
the  same  elements  as  mental  compounds,  are  subject  to  the 
same  universal  and  necessary  laws,  and  nature,  in  this  aspect, 
is  nothing  more  than  applied  arithmetic,  geometry,  and  me- 
chanics. 

It  remains  to  be  seen  whether  nature  is  not  more  than 
this.  Now,  as  far  as  we  can  judge,  and  according  to  recent 
discoveries,  all  changes  of  a  body,  physical,  chemical,  or  vital, 
are  reduced  to  movements  of  its  molecules ;  and  so  again, 
heat,  light,  chemical  affinities,  electricity,  gravity  itself  per- 
haps, all  forces  producing  these  changes  and  producing  move- 
ment itself,  are  reduced  to  movements.  Hence  it  follows 
that  in  visible  nature  there  are  nothing  but  bodies  in  mo- 
tion, bodies  motor  or  movable,  motor  and  movable  in  turn, 
motor  when  their  preliminary  motion  is  the  condition  of  the 
motion  of  another,  movable  when  their  consecutive  motion 
is  the  effect  of  the  motion  of  another ;  which  reduces  all 
corporeal  change  to  the  passage  of  a  certain  quantity  of 
motion  transferred  from  the  motor  to  the  movable  body,  an 
operation  which,  as  we  are  assured,  takes  place  without  gain 
or  loss,  so  that  at  the  end  of  the  circuit,  the  expenditure  is 
exactly  covered  by  the  receipt,  and  the  final  force  is  found 
to  be  equal  to  the  initial  force. — If  this  admirable  reduction 
were  true,  first  for  our  world,  and  then  besides  for  all  beyond 
our  world,  not  only  all  our  physical,  chemical,  and  physiolo- 


CHAP.  III.]  THE  EXPLANATORY  REASON.  50? 

gical  problems,  but  further  all  problems  concerning  any 
actual  body  whatever,  would  be  at  bottom  pure  mechanical 
problems.  Observable  compounds  would  differ  in  nothing, 
except  complication,  from  constructed  compounds  ;  and  just 
as  the  formation,  properties,  alterations,  and  transformations 
of  every  mental  compound,  whether  arithmetical,  geometri- 
cal, or  mechanical,  have  their  reason  of  existence,  so  would 
there  be  a  reason  of  existence  for  the  formation,  properties, 
alterations,  and  transformations  of  every  real  compound. 

III.  We  have  here  considerable  probabilities,  and  may 
sum  them  up  by  saying  that  there  is  no  analogy  to  authorize 
our  supposing  the  absence,  in  any  case,  of  the  explanatory 
reason,  while  many  analogies  lead  us  to  suppose  its  presence 
in  all  cases.  Still  we  have  here  probabilities  only,  and  must 
examine  whether  the  enounced  principle  has  no  better  sup- 
port. On  commencing  any  new  inquiry,  scientific  men  as- 
sume the  principle,  and  indeed,  are  compelled  to  do  so  ;  for, 
without  it,  as  we  have  seen,  they  could'  not  perform  induc- 
tion.* Given  any  phenomenon,  they  invariably  assume  be- 
forehand conditions  forming  its  reason  of  existence  and  whose 
reunion  is  sufficient  to  produce  it,  so  that  the  phenomenon 
cannot  fail  in  any  of  the  cases  in  which  these  conditions  are 
reunited.  "  There  is  an  absolute  determinism,"  says  Claude 
Bernard,f  "  in  the  conditions  of  existence  of  natural  phe- 
nomena, as  well  for  living,  as  for  inanimate  bodies.  .  .  .  When 
the  condition  of  a  phenomenon  is  once  known  and  fulfilled, 
the  phenomenon  must  invariably  and  necessarily  be  repro- 
duced at  the  will  of  the  experimenter.  ....  Phenomena 
can  never  contradict  one  another  if  they  are  observed  under 
the  same  conditions  ;  if  they  exhibit  variations,  this  neces- 
sarily depends  on  the  intervention  or  interference  of  other 
conditions  which  cloak  or  modify  these  phenomena.  Hence 
there  is  room  for  attempting  to  know  the  conditions  of  these 
variations ;  for  we  could  not  have  the  effect  there,  without 
a  cause.  This  determinism  thus  becomes  the  basis  of  all 
scientific  progress  and  criticism.  If,  on  repeating  an  experi- 


*  Part  ii.  book  iv.  chap.  ii.  p.  434,  ante. 
\  "  Introduction  a  1'etude  de  la  Medecine  Experimentale,"  pp.  115  et  seg. 


50S  THE  KNOWLEDGE   OF  GENERAL  THINGS.       [BOOK  IV. 

ment,  we  find  discordant  or  even  contradictory  results,  we 
ought  never  to  admit  real  exceptions  or  contradictions,  for 
this  would  be  anti-scientific  ;  we  must  simply  and  necessarily 
conclude  that  there  are  differences  of  conditions  in  the  phe- 
nomena, which  may  or  may  not  here  explain  them.  .  .  .  As 
soon  as  the  laws  are  known,  we  cannot  have  exceptions.  .  .  . 
We  must  forcedly  admit  as  an  axiom  that,  in  identical  con- 
ditions, every  phenomenon  is  identical,  and  that  as  soon  as  the 
conditions  are  no  longer  the  same,  the  phenomenon  ceases 
to  be  identical."  We  see  that  the  words  necessarily,  forcedly, 
axiom,  are  here  employed. — Helmholtz  employs  equivalent 
expressions.*  According  to  him,  we  cannot  otherwise  con- 
ceive the  world.  Our  eyes  cannot  perceive  extension  except 
as  colored  ;  and  so,  our  intelligence  cannot  conceive  facts  ex- 
cept as  explicable.  There  is  nothing  conceivable  by  us  ex- 
cept what  is  explicable,  just  as  there  is  nothing  visible  by  us 
except  what  is  colored.  The  internal  eye  has,  like  the  ex- 
ternal, its  innate  structure  from  which  it  cannot  be  set  free, 
and  which  imposes  on  all  its  conceptions  a  necessary  charac- 
ter. Helmholtz  seems  here  to  believe  that  this  constraint 
has  for  ultimate  cause,  the  structure  of  our  mind. — With 
him  and  Claude  Bernard,  we  recognize  the  constraint  as  a 
fact ;  but  we  do  not  conceive  its  ultimate  cause  to  be  in  the 
structure  of  our  mind  ;  for  we  have  already  seen  many  analo- 
gous necessities  of  belief.  There  is  one  such  for  each  of  the 
axioms  of  mathematics ;  they  all  exert  on  our  mind  the  same 
ascendancy  as  the  axiom  of  explanatory  reason;  and  still, 
we  have  demonstrated  them ;  we  have  shown  that  they  have 
a  foundation  in  things,  that  they  are  valid,  not  only  for  us, 
but  in  themselves,  that  their  empire  is  absolute,  not  only 
over  our  intelligence,  but  also  over  nature,  that  if  the  two 
ideas  by  which  we  conceive  them  are  forcedly  connected,  it  is 
because  the  two  data  which  constitute  them  are  also  forcedly 
connected,  and  that,  if  the  constraint  experienced  by  our 
mind  in  their  presence  has,  as  first  cause,  our  mental  struct- 
ure, it  has,  as  ultimate  cause,  the  adjustment  of  our  mental 
structure  to  the  structure  of  things.  It  is  probable,  then, 


"  Fhysiologische  Optik,"  p.  455. 


CHAP.  III.]  THE  EXPLANATORY  REASON.  509 

that  this  great  axiom  is  of  the  same  nature  as  the  rest,  and 
that  analysis  will,  as  with  the  rest,  be  sufficient  to  demon- 
strate it. 

Take  a  couple  of  actually  connected  data,  one  subject  or 
less  general,  the  other  attribute  or  more  general.  We  ex- 
press the  same  thing  by  saying  that  the  subject  possesses 
the  attribute.  This  attribute  may  be  more  or  less  transitory 
or  permanent  ;  for  instance,  in  this  falling  drop  of  rain,  the 
fall  is  an  entirely  momentary  and  transitory  attribute,  since 
it  is  at  an  end  when  once  the  drop  has  touched  the  earth ; 
the  chemical  structure  is  a  more  permanent  attribute,  since  a 
chemical  combination  or  decomposition  is  needed  to  destroy 
it ;  weight  is  an  entirely  permanent  attribute,  since  there  is 
no  known  circumstance  which  can  suppress  it. — Here,  as  in 
all  true  propositions,  the  subject  possesses  the  attribute, 
whether  transitory  or  permanent,  and,  as  we  see,  the  attri- 
bute is  more  general  than  it,  that  is  to  say,  common  to  other 
subjects  than  it. — I  say  now  that  there  is  an  explanatory  rea- 
son for  this  possession  of  the  attribute  by  the  subject,  and, 
by  explanatory  reason,  is  meant,  as  we  have  shown,  one  or 
more  characters  of  the  subject,  included  in  it  like  a  fragment 
in  a  whole,  more  abstract  and  more  general  than  it,  and 
which,  being  themselves  connected  to  the  attribute,  connect 
the  attribute  to  the  subject.  This,  then,  amounts  to  saying 
that  the  attribute  is  not  connected  to  the  whole  entire  sub- 
ject itself,  but  to  one  or  more  abstract  and  general  characters 
of  the  subject. 

To  demonstrate  this  proposition,  let  us  analyze  in  turn 
the  attribute  and  the  subject.  We  have  said  that  the  attri- 
bute is  common  to  the  subject  and  to  others.  This  means 
that  it  is  the  same  in  the  subject  and  in  others.  Thus  the 
fall,  the  chemical  structure,  the  weight,  are  the  same  in  one 
drop  of  rain  and  in  its  neighbors.  Thus  the  equality  of  the 
opposite  sides  is  the  same  .in  this  parallelogram  and  in  all 
parallelograms,  in  the  right-angled  parallelogram  and  in  the 
parallelogram  whose  angles  are  not  right.  Therefore,  to  say 
that  the  subject  possesses  an  attribute  common  to  it  and  to 
others,  is  to  say  that  other  subjects,  real  or  possible,  pos- 
sess the  same  attribute  as  it.  The  equality  of  the  opposite 


510  THE  KNOWLEDGE   OF  GENERAL    THINGS.      [BOOK  IV. 

sides  is  the  same  in  my  parallelogram  and  in  this  other  one ; 
the  chemical  structure  is  the  same  in  my  drop  of  rain  and  in 
this  other  one.  In  other  words,  taken  in  itself,  with  the 
omission  and  suppression  of  the  distinct  subjects  in  which 
they  reside,  the  equality  of  the  opposite  sides  of  my  parallel- 
ogram is  confounded  with  the  equality  of  the  opposite  sides 
of  the  other,  and  the  chemical  structure  of  my  drop  of  rain 
is  confounded  writh  the  chemical  structure  of  the  other,  just 
as  a  particular  triangle,  when  detached  from  the  position  it 
occupies,  and  transferred  by  superposition  upon  some  other, 
coincides  with  the  other  and  is  absolutely  confounded  with  it. 

Let  us  now  consider  the  subject.  What  we  call  a  subject, 
a  distinct  subject,  is  a  sum  or  reunion  of  characters  which  do 
not  all  occur  rigorously  the  same  in  any  other  subject,  how- 
ever similar  we  may  imagine  it.  This  drop  of  rain,  even  if 
we  suppose  it  to  have  a  form,  volume,  temperature,  and  in- 
ternal structure,  exactly  the  same  as  the  one  next  to  it,  or  fol- 
lowing it,  further  possesses  characters  which  are  not  possessed 
either  by  the  one  next  to  it  or  the  one  following  it,  namely, 
its  situation  in  time  with  reference  to  those  preceding  it,  and 
in  space,  with  reference  to  those  surrounding  it.  This  par- 
allelogram, even  if  we  suppose  its  sides  precisely  the  same  in- 
length  and  its  angles  exactly  the  same  in  expansion  as  the 
sides  and  the  angles  of  the  other,  possesses  in  addition  at  least 
one  character  which  the  other  does  not  possess,  namely,  its 
particular  position  in  space,  on  my  paper,  or  on  this  board. 
The  analysis  is  the  same,  if  in  this  place  of  an  individual 
subject,  as  this  drop  of  rain  or  this  parallelogram,  we  consider 
a  more  or  less  general  subject,  like  the  parallelogram  in  itself 
or  water  in  general.  Water  is  liquid  like  mercury,  and  the 
parallelogram  has  its  opposite  sides  equal  like  the  regular 
hexagon  ;  but  water  compared  with  mercury,  just  as  the 
parallelogram  compared  with  the  regular  hexagon,  is  a  distinct 
subject,  which,  being  distinct,  forcedly  possesses,  like'this  drop 
of  rain,  one  or  more  characters  by  which  it  is  distinguished 
from  every  other  more  or  less  similar  subject  with  which  it  is 
compared. 

Here,  then,  we  arrive  at  this  conclusion,  that  our  sub- 
ject, being  distinct  from  another  subject,  is  not  the  same,  and 


CHAP.  III.]  THE  EXPLANATORY  REASON  tu 

nevertheless,  possesses  the  same  attribute.  Let  us  replace  the 
terms  by  their  definition.  Distinct  subject,  signifies  sum  or 
reunion  of  characters  of  which  one  or  more  are  absent  in  the 
other  subject ;  it  is  to  this  sum  or  reunion  that  the  attribute 
directly  or  indirectly  appertains.  Hence  three  possible  hy- 
potheses, and  three  hypotheses  only. — Either  the  attribute 
appertains  directly  to  the  sum  of  reunited  characters ;  or  it 
appertains  indirectly,  that  is,  by  appertaining  to  that  portion 
of  the  sum  which  is  composed  of  characters  absent  in  the 
other  subject,  or  by  appertaining  to  the  other  portion.  Now 
the  two  first  hypotheses  are  contradictory. — In  fact  on  the 
one  hand,  the  attribute  cannot  appertain  to  that  portion  of 
the  sum  which  is  composed  of  the  characters  absent  in  the 
second  subject ;  for  then  it  would  not  appertain  to  the  second 
subject,  in  which  those  characters  are  wanting;  now,  by 
definition,  the  attribute  belongs  to  that  subject. — On  the 
other  hand,  the  attribute  cannot  belong  to  the  sum  of  the 
united  characters  ;  for  then  it  would  not  belong  to  the  second 
subject,  in  which  this  reunion  is  wanting ;  now,  by  definition, 
it  belongs  to  that  subject. — These  two  suppositions  being 
excluded,  the  third  alone  remains.  Hence  it  follows  that  the 
attribute  belongs  to  that  portion  of  our  subject  which  is 
composed  of  characters  present  in  it  and  in  the  second  sub- 
ject, that  is  to  say  common  to  both,  that  is  to  say,  general. 
Hence  it  also  follows  that  it  appertains  solely  to  a  portion  of 
our  subject,  in  other  words  to  a  fragment,  to  an  extract,  to 
an  abstract  included  in  our  subject ;  which  is  what  had  to  be 
proved.* 


*  We  have  just  demonstrated  the  axiom  by  means  of  the  notion  of  identity ; 
we  can  also  demonstrate  it  by  means  of  the  notion  of  indifference  ;  and  this  sec- 
ond demonstration  is  well  suited  to  the  particular  form  under  which  the  axiom, 
has  been  presented  by  Claude  Bernard. 

When  given  a  subject  under  certain  circumstances,  take  a  second  subject 
exactly  similar  to  the  first,  and  in  circumstances  exactly  similar  to  the  first  circum- 
stances, so  that  there  may  be  no  difference  between  the  first  and  second  case  but 
that  of  time  or  place.  Let  us  further  assume  that  this  difference  is  indifferent, 
that  is  to  say,  without  influence  or  any  event  which  occurs  in  the  first  subject,  and 
that,  in  relation  to  this  event,  it  may  be  considered  as  null, — This  supposition  is 
not  always  true  ;  the  time  and  position  have  often  an  influence  ;  the  same  heavy 
body  falls  more  quickly  in  the  second  minute  than  in  the  first  ;  the  same  penclu- 


5i2  THE  KNOWLEDGE  OF  GENERAL   THINGS.      [BOOK  TV. 

The  axiom,  thus  demonstrated  and  understood,  is  readily 
seen  to  reduce  itself  to  the  enunciation  of  the  consequences 
of  a  mental  construction.  Just  as  with  other  axioms,  it 
develops  a  pure  supposition ;  this  it  develops  by  detecting 
something  the  same  in  the  two  data  it  connects,  and  it  is  re- 
duced to  the  principles  of  identity,  of  the  alternative,  and  of 
contradiction.  So  again,  it  lays  down  no  datum  as  real ;  all  it 
establishes  is  an  outline  to  which  real  data  may  adapt  them- 
selves. It  does  not  affirm  that  there  are  in  fact  distinct 
subjects,  nor  that  two  or  more  distinct  subjects  possess  in 
fact  the  same  attribute.  Experience  alone  can  instruct  us  as 
to  this. — But,  when  experience  has  instructed  us,  and  when, 
on  considering  all  the  propositions  of  our  experimental 
sciences,  we  find  throughout  nature  distinct  subjects  pos- 
sessed of  the  same  attribute,  then  the  axiom  applies  :  being 
demonstrated  like  a  geometrical  axiom,  it  has  the  same  range, 
and,  like  a  geometrical  axiom,  it  extends  its  empire,  not  only 
over  all  fragments  of  duration  and  extension  which  are  acces- 
sible to  our  observation,  but  beyond  and  to  infinity,  to  all 
points  of  duration  and  extension  in  which  two  distinct  subjects 
present  the  same  attribute. 

Hence  follow  vast  consequences,  and  first  of  all  the  proof 
of  the  principle  on  which  induction  rests.  We  had  only  sup- 
posed it  true,  provisionally  and  by  analogy  ;*  we  had  only 
assumed  that  a  general  character  invariably  indicates  the 
presence  of  another  general  character  to  which  it  is  connec- 
ted ;  we  are  now  able  to  demonstrate  this  presence. — A  gen- 


lum  oscillates  differently  at  the  bottom  of  a  mine  and  at  the  summit  of  the  adjacent 
mountain. — But  subsequent  experiences  intervene  to  confirm  or  contradict  our 
supposition,  and,  whether  confirmed  or  contradicted,  we  shall  learn  something  by 
it.  Meanwhile,  let  us  consider  it  as  a  pure  mental  construction,  and  see  what 
follows  from  it.  Since,  by  supposition,  the  difference  of  the  two  cases  has  no 
influence  or  is  null,  the  second  case  is  absolutely  and  rigorously  confounded 
with  the  first,  and  may  be  substituted  for  it  as  legitimately  as  any  triangle  may 
for  another  equal  and  similar  triangle  ;  therefore,  the  event  which  occurs  in  the 
first  subject  will  also  occur  in  the  second,  or,  to  use  Claude  Bernard's  expression, 
"  in  identical  conditions,  phenomena  are  identical." — The  reader  will  observe  the 
analogy  of  the  axiom  thus  enounced  and  proved  with  the  above  demonstrated 
axioms  of  mechanics. 

*  Part  ii.  book  iv.  ch.  ii.  p.  434  ante. 


CHAP.  III. J  THE  EXPLANATORY  REASON. 

eral  character  is  an  attribute,  the  same  in  several  distinct 
subjects.  Now,  according  to  the  axiom,  it  does  not  appertain 
to  such  or  such  a  distinct  subject  directly,  but  to  all  indirectly 
by  the  intermediate  link  of  a  portion  common  to  them,  and 
which,  in  this  respect,  is  a  general  character ;  in  this  way,  it 
supposes  the  presence  of  another  general  character  to  which 
it  belongs;  thus,  its  presence  is  sufficient  to  guarantee  to  us 
the  presence  of  this  other. — Moreover,  this  other  character 
to  which  the  first  appertains  is  general ;  in  other  words,  the 
first  appertains  to  the  second,  whatever  be  the  subject,  what- 
ever the  medium,  whatever  the  place,  whatever  the  moment ; 
in  other  words  again,  the  presence  of  this  other  is  sufficient 
to  involve,  and  therefore  to  guarantee  to  us,  the  presence  of 
the  first. — Thus,  in  general,  the  presence  of  the  one,  which 
is  already  known,  is  sufficient  to  guarantee  to  us  the  presence 
of  the  other,  which  is  as  yet  unknown,  and  which  we  are 
attempting  to  discover.  Now,  we  have  seen  that  on  this 
sufficiency  are  founded  all  the  processes  of  elimination,  the 
methods  of  agreement  and  difference,  of  which  induction  is 
composed. 

On  the  other  hand,  take  any  subject  considered  at  two 
successive  moments,  and  in  which  some  particular  attribute 
is  the  same  at  both  moments,  that  is  to  say  common  to  the 
two  moments,  and  consequently,  general.  After  what  we 
have  just  said,  this  attribute  has  its  condition,  which  is  a 
character  common  to  both  moments  of  the  subject ;  and,  as 
its  condition  is  sufficient  to  involve  it,  while  its  condition 
persists,  it  will  itself  persist.  Consequently,  if,  in  fact,  at  the 
third  moment  it  ceases  to  exist,  this  is  because  its  condition 
has  ceased  to  exist ;  hence  it  finally  follows  that  the  suppres- 
sion of  a  character  has,  as  condition,  the  suppression  of  another 
character.  Now  every  alteration  in  a  subject  is  the  suppres- 
sion of  one  of  its  characters,  so  that  every  alteration  has  a 
condition,  which  we  express  by  saying  that  it  has  a  cause, 
and  that  this  cause  is  another  alteration.  Here  we  have  the 
axiom  of  causalty ;  considered  with  reference  to  the  axiom 
of  explanatory  reason,  it  is  a  consequence  and  an  application 
of  that  axiom.  That  axiom  has  many  others.  Leibnitz, 
who  termed  it  Principle  of  Sufficient  Reason,  constructed 
33 


514  THE  KNOWLEDGE  OF  GENERAL  THINGS.     [BOOK  IV. 

from  it  all  his  idea  of  the  universe.  And,  in  fact,  it  is  by 
this  axiom  that  we  arrive  at  the  highest  conception  of  a 
general  aggregate,  at  the  idea  of  one  necessary  whole,  at  the 
persuasion  that  existence  is  itself  explainable.  For,  since 
existence  is  a  general  character,  and  the  most  general  of  all 
characters,  we  must  conclude  from  our  axiom  that  it  has,  like 
every  general  character,  its  condition  or  explanatory  reason, 
other  than  itself.  Mathematicians  assume  nowadays  that 
real  quantity  is  only  a  case  of  imaginary  quantity,  a  special 
and  singular  case,  in  which  the  elements  of  imaginary  quantity 
present  certain  conditions  which  are  wanting  in  the  other 
cases.  May  we  not  similarly  assume  that  real  existence  is 
only  a  case  of  possible  existence,  a  special  and  singular  case, 
in  which  the  elements  of  possible  existence  present  certain 
conditions  which  are  wanting  in  the  other  cases  ?  With  this 
assumption,  may  we  not  inquire  into  these  elements  and  these 
conditions  ?  We  are  here  on  the  threshold  of  metaphysics. 

We  will  not  enter  ;  we  are  here  concerned  with  cognitions 
alone.  The  reader  has  seen  how  they  are  formed,  and  by 
what  adjustments  they  correspond  to  things.  They  have,  as 
materials,  sensations  of  various  kinds,  some  primitive  and 
excited,  others  spontaneous  and  reviving,  attached  to  one 
another,  counterbalanced  by  one  another,  purposely  organized 
by  their  connections  and  their  antagonism,  composed  of  ele- 
mentary sensations  smaller  than  themselves,  these  again  of 
still  smaller  ones,  and  so  on,  till  their  differences  are  finally 
effaced  and  permit  us  to  divine  the  existence  of  wholly  similar 
infinitesimal  elements  whose  various  arrangements  explain 
their  various  aspects.  —  Thus  in  a  cathedral,  the  ultimate 
elements  are  grains  of  sand  agglutinated  into  stones  of  various 
forms,  which,  attached  in  pairs,  form  masses,  whose  thrusts 
oppose  and  balance  each  other  ;  all  these  associations  and  all 
these  mutual  pressures  being  co-ordinated  in  one  grand  har- 
mony. Such  is  the  simplicity  of  the  means,  and  such  the 
complication  of  the  effect,  and  both  the  simplicity  and  the 
complication  are  as  admirable  in  the  mental  as  in  the  real 
edifice. 


THE   END. 


30112063006347 


